Non-staining coating composition

ABSTRACT

An anti-contamination coating composition is obtained by mixing a tetraalkoxysilane condensate having an average condensation degree of 4 to 20 and has an alkyl group having 1 to 2 carbon atoms and an alkyl group having 3 to 10 carbon atoms, or an alkyl group having 1 to 3 carbon atoms and an alkyl group having 4 to 12 carbon atoms, the alkyl group having 3 to 10 carbon atoms or 4 to 12 carbon atoms present in the amount of 5 to 50% by equivalent based on all alkyl groups in the condensate, with a polyurethane resin, an acrylic copolymer resin or a silicone-acrylic copolymer resin in the amount of 1.0 to 40.0 parts by weight in term of SiO 2  relative to 100 parts by weight of the polyol compound. The addition of a hydrophilic alkoxysilane having a poly alkylene oxide chain compound is also suitable. The coating composition forms an anti-contamination coat having hydrophilicity on the surface, soil-release effect and excellent stain resistance to oil, and is also suitable for outside wall coating of buildings, having excellent interlaminar adhesion when multiple coatings are applied.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of co-pending U.S. patent applicationSer. No. 09/125,548 filed Aug. 27, 1998, now U.S. Pat. No. 6,271,292granted Aug. 7, 2001, which is the national phase of PCT/JP97/04247filed Nov. 20, 1997.

TECHNICAL FIELD

The present invention relates to an anti-contamination coatingcomposition used for surface finishing of various materials such asmetal, glass, porcelain tile, concrete, sideboard, extrusion-moldedplate, plastic and the like. More particularly, it relates to ananti-contamination coating composition used for coating finishing ofstructures such as building structures, bridges and the like, which canalso be coated directly on a substrate and can also be used in a coatingcomposition used as a final finishing coating such as various finishingcoatings, pattern coating, coating for forming the stone-like surface,coating for forming the patterned surface or the like.

BACKGROUND ART

Coating finishing has hitherto been performed to protect a substrate ofbuilding structures, or civil engineering structures, and to impartdesign and to improve the appearance. However, a large amount of oilycontaminants have recently been floating in the air as a result of anexhaust gas discharged from automobiles in the center of the city andsuburbs thereof. When those oily contaminants adhere to the surface ofthe coat formed by using a high-durability coating, a considerable sootyor striped contamination (hereinafter referred to as “rain-stripedcontamination”) occurs, therefore, the coating finishing provided toimprove the scene of the city was meaningless sometimes.

Japanese Patent Kokai Publication No. 4-370176 discloses a coatingcomprising a segmented polymer containing a hydrophilic segment such aspolyalkylene oxide segment and a hydrophobic segment such aspolysiloxane. This coating is capable of obtaining such an effect thatwater derived from rainfall penetrates/flows into the interface betweenthe coat and contaminants to wash off contaminants together with water(soil release effect) by imparting the hydrophilicity to the coatsurface. Although the hydrophilicity is imparted when water is presenton the coat surface, the hydrophobicity is actually imparted when thecoat surface has no opportunity to contact with water for a long periodof time. Therefore, there is a problem that it takes a considerably longtime to convert the hydrophobicity of the coat surface into thehydrophilicity during rainfall , so that the contamination duringrainfall can not be prevented.

Japanese Patent Application No. 6-506632 (International PublicationWO94/06870) discloses an anti-contamination coating composition whereinorganosilicate is added in the coating and the coat surface ishydrophilized by the reaction thereof and, furthermore, a soil releaseeffect is utilized. The organosilicate forms a silanol group or asiloxane bond by the hydrolysis reaction in the presence of an acidcatalyst, and this silanol group or siloxane bond imparts thehydrophilicity to the coat surface. Taking actual coating on the outsidewall of buildings into consideration, the reaction may proceed by acidicrain, but it takes a considerably long period of time after formation ofthe coat to obtain the hydrophilic surface enough to sufficiently exertthe soil release effect, similar to the above technique.

Japanese Patent Kokai Publication No. 6-145453 discloses a method ofmixing an acrylic silicone resin with organosilicate to obtain ahydrophilic coat. According to this technique, a large amount oforganosilicate is required to impart sufficient hydrophilicity to thecoat. However, when a large amount of organosilicate is added, thecrosslink density of the coat becomes too large and the coat becomesbrittle. At the same time, a large amount of siloxane bonds areintroduced to cause deterioration of the chemical resistance of thecoat, which results in deterioration of the weathering resistance of thecoat as contradiction.

In such a way, among coats formed by using conventionalanti-contamination coating, those requiring a long period of time tohydrophilize the surface can cause rain-striped contamination within avery short period of time after application of the coating.

Originally, the anti-contamination coating has the effect of causing nocontamination, and users and builders who request the coating expectthat effect. Accordingly, the fact that contamination arises even at theinitial stage after formation of the coat fails to meet the expectationof these users and builder temporarily, and the fact also imparts asense of unease to the anti-contamination effect for a long period oftime. Since a conventional anti-contamination coating has a main objectof washing out contaminants by rainfall, the anti-contamination coatingis inferior in stain resistance of once adhered contamination. It hasbeen found that, when there is no rainfall for a long period of time,oily contamination penetrates into the coat to cause contamination whichis hardly washed out by rainfall no longer.

An object to be solved by the present invention is to obtain ananti-contamination coating composition for providing ananti-contamination coat, which has a soil release effect of washing outcontaminants because the surface exerts the hydrophilicity immediatelyafter formation of the coat, not showing hydrophilicity by an actionformed after formation of the coat, such as waterfall, and which isstrong but not brittle because of its specific crosslinked structure,and has excellent stain resistance to oily contamination, goodweathering resistance and good coat physical properties.

Another object to be solved by the present invention is to provide acoating composition which can improve the interlaminar adhesion(hereinafter referred to as a “recoating property”) when multi-layercoating is performed on a topcoat layer after curing an undercoat layerusing a reaction curing type polyurethane or polyurethane-acrylicanti-contamination coating, and effectively prevent blister, crack orlifting (a phenomenon wherein shrinkage occurs on the coat surface as aresult of dissolution of the uncured portion of the undercoat layer by asolvent of the coating of the topcoat layer because of insufficientcuring and adhesion of the coat of the undercoat layer in case ofmultiple coating) caused with a lapse of time.

Such an anti-contamination high-durability coating is exclusively asolution type of an organic solvent. With recent enhancement of theenvironmental awareness, there have been used those using as weak asolvent as possible. Furthermore, it has been required to convert intoan aqueous coating.

It is generally considered that, when organosilicate (i.e. alkylsilicate) is added in the coating, it reacts with water in the airduring the formation of the coat, and an alkoxysilyl group Si—OR isconverted into a silanol group Si—OH and alkyl silicates having asilanol group are arranged on the coat surface, thereby exhibiting thehydrophilicity.

It is assumed that, when using a resin which is only dissolved in asolvent having high dissolving power, since the coat is certainlyhydrophilic and the anti-contamination effect can also be obtained, sucha surface orientation occurs. When using a urethane resin using a polyolhaving a solubility parameter of about 6.5 to 9.5, which is alsodissolved or dispersed in a solvent having low dissolving power, therearise white turbidity of a film and such phenomenon that theanti-contamination is not obtained. Therefore, there is much room forimprovement.

A finishing coating material whose main material layer has rubberelasticity referred to as a waterproofing multi-layer coating material,which is used in coating finishing performed in the case of a substrateof building structures, civil engineering structures, etc., has beennoted and widely used because it has a follow-up property to crazing(hereinafter referred to as “crack”) of the outside wall of concrete andan effect for inhibition of penetration of a carbon dioxide gas.

This waterproofing multi-layer coating material is composed of anundercoat layer, a main material (a continuous layer and a patternedlayer, which have rubber elasticity) and a topcoat material, but thetopcoat layer is coated with an elastic coating following the mainmaterial layer. When coating finishing is performed on the whole outsidewall including the butt portion (joint portion) between boards joined byusing a sealing material in a dry technique using a dry buildingmaterial represented by sideboard, extruded plate, etc., an elasticcoating capable of following movement of the sealing material drivenportion is used. Furthermore, an elastic coating is often used to a rawmaterial such as metal, wherein degree of expansion and shrinkage iscomparatively large, and to a substrate whose structural movement isassumed.

However, there is a problem in that the coat obtained from these elasticcoatings is generally inferior in resistance to surface contamination toa rigid coat.

Under these circumstances, the present inventors have found that, bymixing a hydrophilic alkoxysilane compound containing an alkylene oxidechain with an acrylic silicone resin and an alkyl silicate(organosilicate), as described in Japanese Patent Kokai Publication No.9-31401, hydrophilization is exhibited from the comparatively initialstage in the coat surface to be formed from the composition. However,there was much room for improvement in anti-contamination performanceimmediately after formation of the coat.

The alkyl silicate (organosilicate) used in a conventionalanti-contamination coating is closely related to brittleness of theformed coat, depending on the amount and combination with the kind ofthe used resin. Therefore, there is a fear of causing crack in the coat.Furthermore, the alkyl silicate (organosilicate) is very expensive as araw material for coating and, therefore, it was a large problem tocoating makers in view of the raw material cost.

That is, the problems to be solved by the present invention are asfollows.

(i) To obtain an anti-contamination coating composition for providing ananti-contamination coat, which has a soil release effect of washing outcontaminants because the surface exerts the hydrophilicity immediatelyafter formation of the coat, not showing hydrophilicity by an actionformed after formation of the coat, such as rainfall, etc., and hasexcellent stain resistance to oily contamination, good weatheringresistance and good coat physical properties.

(ii) To provide a coating composition, which can improve theinterlaminar adhesion (hereinafter referred to as a “recoatingproperty”) when multi-layer coating is performed, and effectivelyprevent blister, crack or lifting caused with a lapse of time.

(iii) To provide a coating composition, which has characteristics of theabove items (i) and (ii), and can use a weak solvent which hardly causesenvironmental problems.

(iv) To provide a coating composition, which has characteristics of theabove items (i) and (ii), and forms an elastic coat which hardly causescrazing with a lapse of time.

(v) To provide a coating composition, which exerts the same effect evenif the amount of an expensive silicate compound mixed becomes lower inorder to exhibit excellent soil-release effect immediately afterformation of the coat, and also contributes to reduce the cost.

DISCLOSURE OF INVENTION

The present inventors have intensively studied to solve contaminationimmediately after coating as an object of coating obtained by mixingorganolisilicate or a condensate thereof with an organic coating base.As a result, the present inventors have found that coating having veryexcellent anti-contamination effect immediately after coating isobtained by mixing a tetraalkoxysilane condensate (C1) or (C2), which isa condensate of a tetraalkoxysilane with a combination of a short-chainalkyl group and a long-chain alkyl group in place of the alkyl group,not a tetraalkoxysilane or a simple condensate thereof, with coating.Thus, the present invention has been accomplished.

The present invention is composed of a combination of the followingresins and additives.

(1) A composition which is mainly composed of a combination of apolyurethane-forming component (PU-I) and (C1).

(2) A composition which is mainly composed of a combination of apolyurethane-forming component (PU-II) and (C2). This composition ischaracterized in that a weak solvent can be used, particularly.

(3) A composition which is composed of a combination of apolyurethane-forming component (PU-III) and (C1) and polycaprolactonediol and/or polycaprolactone polyol as an essential component. Thiscomposition forms a coat having elasticity, particularly.

(4) A composition which is mainly composed of a combination of anacrylic copolymer resin (AC) and (C1).

(5) A composition which is mainly composed of a combination of analkoxysilyl group-containing acrylic copolymer resin (AS) and (C1).

The present invention will be described in detail hereinafter.

The anti-contamination coat composition of the present inventioncomprises a polyol compound (A1), a polyisocyanate compound (B1) and atetraalkoxysilane condensate (hereinafter referred to as an“alkoxysilane condensate” or an “alkyl silicate condensate”, sometimes),wherein the polyol compound and polyisocyanate compound are contained ina ratio of 0.6 to 1.4 in terms of a NCO/OH ratio and thetetraalkoxysilane condensate is contained in the amount of 1.0 to 40.0parts by weight in term of SiO₂ relative to 100 parts by weight of thecontent of the polyol compound, and wherein the polyol compound (A1) hasa weight-average molecular weight of 5000 to 80000 and a hydroxyl groupvalue of 20 to 150 (KOH mg/g) and the tetraalkoxysilane condensate is atetraalkoxysilane condensate (C1), which has an average condensationdegree of 4 to 20 and has an alkyl group having 1 to 2 carbon atoms andan alkyl group having 3 to 10 carbon atoms, the alkyl group having 3 to10 carbon atoms being contained in the amount of 5 to 50% by equivalentbased on all alkyl groups in the condensate.

By adopting such a construction, there can be obtained a coating, whichis extremely superior in effect of preventing contamination immediatelyafter coating to the case where a hydrophilic alkoxysilane compoundalone or its condensate is added, and which has a soil-release effectand is also superior in stain resistance to oily contamination,weathering resistance and other coat physical properties.

When the molecular weight of the above polyol is smaller than 5000, thecuring property and durability of the coat are not sufficient. On theother hand, when the molecular weight is larger than 80000, thefinishing property of the coat is not sufficient. Considering the changeof the other raw materials, the molecular weight is preferably withinthe range from 20000 to 60000 because the coat having stablecharacteristics is formed.

When the hydroxyl group value is less than 20 KOH mg/g, the durabilityand contamination resistance of the coat are poor. On the other hand,when the hydroxyl group value exceeds 150 KOH mg/g, the durability andflexibility of the coat are insufficient. When the hydroxyl group valueis within the range from 30 to 100 KOH mg/g, particularly excellentcharacteristics can be obtained.

The glass transition point of these polyols is from −10 to 150° C.,preferably from 10 to 100° C. When the glass transition point is lowerthan −10° C., the contamination removing property and contaminationrecovering property are poor. On the other hand, when the glasstransition point is higher than 150° C., the flexibility and durabilityare poor.

It is considered that, in the present invention, when an alkyl grouphaving 1 to 2 carbon atoms and an alkyl group having 3 to 10 carbonatoms coexist in the tetraalkoxysilane condensate, an anti-contaminationcoat having excellent surface orientation property and excellent coatphysical properties can be formed.

The above tetraalkoxysilane condensate (C1) is contained in the amountof 1.0 to 40.0 parts by weight, preferably from 2.0 to 30.0 parts byweight, in terms of SiO₂ relative to 100 parts by weight of the resinsolid content of the polyol (A1).

When the amount is smaller than 1.0 parts by weight, the hydrophilicityis not sufficient and, therefore, the contamination resistance is poor.On the other hand, when the amount exceeds 40.0 parts by weight,problems such as poor appearance of the cured coat, crack and the likearise. When the amount is from 2.0 to 30.0 parts by weight, theinfluence of the material composition is hardly exerted and, therefore,stable characteristics can be obtained.

The hydrophilic alkoxysilane compound (D) containing an alkylene oxidechain can be added to the anti-contamination coating composition of thepresent invention. Because the hydrophilicity is further imparted to thecoat by using in combination with the alkoxysilane condensate (C1), anexcellent effect of preventing contamination can be obtained. By usingit in combination, there can be obtained an anti-contamination coatingcomposition which is particularly superior in stain resistance of thecoat.

The present invention is also directed to an anti-contamination coatingcomposition, wherein the above polyol compound (A1) is a solvent-solublefluorine-containing copolymer obtained by copolymerizing a fluoroolefin,at least one of a vinyl ester and a vinyl ether, and a hydroxylgroup-containing monomer as an essential constituent monomer.

By using a polyol containing fluorine as a polyol component constitutinga polyurethane which is a resin component of coating, the long-termweathering resistance and effect of preventing contamination can befurther improved.

In the coating composition of the present invention, it is aparticularly preferable aspect to add the hydrophilic alkoxysilanecompound (D) having a weight-average molecular weight of 150 to 3500 andcontaining an alkylene oxide chain having repeating units of 2 to 40 inthe amount of 0.1 to 20 parts by weight relative to 100 parts by weightof the above polyol compound (A1).

Use of hydrophilic alkoxysilane compound (D) having a hydrophilicpolyalkylene oxide chain further enhances the hydrophilicity of the coatimmediately after coating thereby to effectively prevent the initialcontamination.

As the component of anti-contamination coating of the present invention,an amine compound (E) is also preferably added in amount of 0.02 to 5.0parts by weight relative to 100 parts by weight of the polyol compound(A1). By using such an amine compound, in addition to the aboveanti-contamination effect, the recoating property is also improved, andblister caused with a lapse of time in case of multi-layer coating,crack and lifting in case of coating two or more layers can be preventedeffectively and, at the same time stiff coat can be formed. Therefore,there can be obtained an anti-contamination coat which is remarkablysuperior in durability.

In spite of the above amine compound, the compound having a tertiaryamino group may be used as a polyol component. The anti-contaminationcoating composition according to the present invention is characterizedin that the polyol compound contains a tertiary amino group-containingacrylpolyol, or the invention relates to the anti-contamination coatingcomposition of the present invention, characterized in that thefluorine-containing copolymer contains a fluorine-containing copolymerhaving a tertiary amino group. By using such a polyol, the same effectas that obtained by adding an amine compound can be obtained.

The present inventors have intensively studied. As a result, they foundthat, in the case of the urethane resin coating using a polyol havingsolubility parameter SP of 6.5 to 9.5, which can be dissolved and/ordispersed in a solvent having particularly weak dissolving force, thecoating surface can be hydrophilized by mixing the tetraalkoxysilane lowcondensate having a specific structure in the coating, thereby making itpossible to provide a coat having good contamination resistance. Thus,the present invention has been completed.

The present invention further relates to an anti-contamination coatingcomposition comprising a polyol compound (A2) having a solubilityparameter SP of 6.5 to 9.5, a weight-average molecular weight of 5000 to150000 and a hydroxyl group value of 15 to 100 (KOH mg/g) dissolvedand/or dispersed in a non-aqueous solvent, a polyisocyanate compound(B2) in a NCO/OH equivalent ratio of 0.7 to 2.0, a tetraalkoxysilanecondensate (C2) which is a condensate of tetraalkoxysilane having anaverage condensation degree of 4 to 10 and which has an alkyl grouphaving 1 to 3 carbon atoms and an alkyl group having 4 to 12 carbonatoms, the alkyl group having 4 to 12 carbon atoms being contained inthe amount of 5 to 50% by equivalent based on all alkyl groups in thecondensate, and a hydrophilic alkoxysilane compound (D) having aweight-average molecular weight of 150 to 3500 and containing analkylene oxide chain having repeating units of 2 to 40, wherein thetetraalkoxysilane condensate (C2) is contained in the amount of 1.0 to50.0 parts by weight in term of SiO₂ and the hydrophilic alkoxysilanecompound (D) is contained in the solid content of 1.0 to 20 parts byweight, respectively, relative to 100 parts by weight of the resin solidcontent of the polyol compound (A2).

The present invention is further characterized by using the same PU-IIbase as described above, and containing 1.0 to 50.0 parts by weight oftetraalkoxysilane condensate (C2) and an amine compound (E) in the solidcontent of 0.02 to 5.0 parts by weight, respectively, relative to 100parts by weight of resin solid content of polyol compound (A2).

When the weight-average molecular weight of A2 is smaller than 5000, asuitable viscosity as the coating is not obtained so that respectivephysical properties of the coat are poor. On the other hand, when it islarger than 150000, the sharpness and gloss of the coat are lowered,unfavorably. When the hydroxyl group value is smaller than 15 KOH mg/g,the crosslink density is low so that various physical properties andcontamination resistance of the coat are poor. On the other hand, whenit is larger than 100 KOH mg/g, the crosslink density becomes higherand, therefore, the durability and flexibility of the coat areinsufficient and, at the same time, the surface orientation property ofthe tetraalkoxysilane condensate (C2) is inhibited, unfavorably.

As the component (A2), those having SP of 6.5 to 9.5 are used. By usingthose having such SP, it is possible to be dissolved and/or dispersed ina solvent having a weak dissolving force referred to as a weak solvent,thereby to prepare a weak solvent type coating. As a matter of course,it is possible to use after dissolving in a strong solvent having astrong dissolving force.

In the urethane resin coating using such a polyol compound (A2), anormal alkyl silicate has poor compatibility and poor surfaceorientation property so that the coat is contaminated. To the contrary,according to the present invention, the compatibility is good andsurface orientation property is excellent and coat is hydrophilized sothat a coat having excellent anti-contamination property can beprovided. Furthermore, it is able to provide a coating compositionhaving excellent various coat performances.

Furthermore, by adding a hydrophilic alkoxysilane compound (D), thesurface of the coat is hydrophilized in the initial stage so that it ispossible to provide an anti-contamination coating composition which issuperior in contamination resistance and stain resistance.

It is also preferred to provide a composition obtained by adding anamine compound (E). When an anti-contamination coating composition ismulti-coated, an effect that interlaminar adhesion becomes good is alsoexerted.

In the present coating compositions, it is suitable that an aliphatichydrocarbon is contained in the amount of 50% by weight or more based onthe whole solvents in the coating compositions. Therefore, lifting doesnot take place, thereby making it suitable for repair and an influenceon the environment can be reduced.

The anti-contamination coating composition of the present invention mayfurther contain a polyurethane-forming component (PU-III) wherein thepolyol compound (A1) is a polyol compound having a glass transitiontemperature (Tg) of 15 to 100° C. and the polyisocyanate compound (B1)has a concentration of a polyisocyanate group of the solid content offrom 3 to 15% by weight, and a polycaprolactone diol and/orpolycaprolactone triol (G) having a weight-average molecular weight of300 to 3000 and a hydroxyl group value of 30 to 550 KOH mg/g arecontained in the amount of 1 to 20 parts by weight relative to 100 partsby weight of the solid content of the polyol compound (A1).

In the present invention, the Tg of the polyol compound (A1) is limited.In the case of the coat having the flexibility, when Tg is lower than15° C., contaminants physically adhere and the contamination resistanceis poor, and the weathering resistance is also deteriorated. On theother hand, when it is higher than 100° C., the crack-following propertyof the undercoat disappears, resulting in poor waterproofing property.

As the polyisocyanate compound (B1), those having a NCO content of 3 to15%, and more preferably 8 to 12%, based on the solid content of 100%are used.

When the NCO content is less than 3%, it is necessary to mix a largeamount of a polyisocyanate compound, resulting in poor durability of thecoat, unfavorably. On the other hand, when the NCO content is more than15%, the coat becomes too hard and, therefore, the expected elastic coatcan not be formed and the waterproofing performance is not obtained.

With regard to the component of polycaprolactone diol and/orpolycaprolactone triol (G), when the weight-average molecular weight isless than 300, it is not preferable because of insufficient flexibilityof the coat. On the other hand, when it is more than 3000, it is notpreferable because finishing feel and workability are not satisfactory.

When the amount of such a component (G) is less than 1 part by weightrelative to 100 parts by weight of the solid content of the component(A1), the flexibility of the coat is insufficient, unfavorably. When theamount exceeds 20 parts by weight, the weathering resistance of the coatis lowered.

The tetraalkoxysilane condensate component (C1) having a specificstructure, wherein alkyl groups having 1 to 2 carbon atoms and thosehaving 3 to 10 carbon atoms coexist, exerts the above effect, therebyobtaining a coating composition capable of forming an anti-contaminationcoat, which is superior in elasticity and physical properties of thecoat. The invention further describes the anti-contamination coatingcomposition wherein a hydrophilic alkoxysilane compound (D) having aweight-average molecular weight of 150 to 3500 and containing analkylene oxide chain having repeating units of 2 to 40 was added in theamount of 0.1 to 20 parts by weight relative to 100 parts by weight ofthe solid content of the polyol compound (A1).

As described above, the anti-contamination performance immediately afterformation of the coat is remarkably improved.

The present invention is further directed to an anti-contaminationcoating composition comprising a tetraalkoxysilane condensate (C1) inthe amount of 1 to 30 parts by weight in terms of SiO₂ relative to 100parts by weight of the solid content of an acrylic copolymer resin (AC)which contains an acrylate and/or a methacrylate monomer and has a glasstransition temperature of 0 to 100° C.

By adopting the above construction, the surface is hydrophilizedimmediately after formation of the coat and the stain resistance is alsoexcellent. Therefore, there can be obtained an anti-contaminationacrylate resin coating composition, which exerts a soil-release effectof wash out contaminants and has good physical properties of the coat.

The anti-contamination coating composition of the present inventionfurther comprises the hydrophilic alkoxysilane compound (D) having aweight-average molecular weight of 150 to 3500 and containing analkylene oxide chain having repeating units of 2 to 40 in the solidcontent of 0.1 to 20 parts by weight.

By adding a hydrophilic alkoxysilane compound (D), theanti-contamination type acrylate resin coating composition having betteranti-contamination performance in the initial stage can be obtained.

The present invention further relates to an anti-contamination coatingcomposition comprising a compound (C1) which is a tetraalkoxysilanecondensate having an average condensation degree of 4 to 20 and whichhas an alkyl group having 1 to 2 carbon atoms and an alkyl group having3 to 10 carbon atoms, the alkyl group having 3 to 10 carbon atoms beingcontained in the amount of 5 to 50% by equivalent based on all alkylgroups in the condensate, in the amount of 1.0 to 20.0 parts by weight,and more preferably 1.0 to 10 parts by weight, in terms of SiO₂ relativeto 100 parts by weight of the solid content of an alkoxysilylgroup-containing acrylic copolymer resin (AS) which has a grouprepresented by the general formula

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; R₂represents a hydrogen atom or a monovalent hydrocarbon group selectedfrom the group consisting of alkyl, aryl and aralkyl groups having 1 to10 carbon atoms; and a represents 0, 1 or 2.

The characteristics of the present invention are as follows. That is,since the anti-contamination performance obtained immediately afterformation of the coat is better than that of an anti-contaminationcoating composition containing a conventional alkoxysilylgroup-containing acrylic copolymer resin and a tetraalkoxysilane, andthe anti-contamination can be obtained by smaller concentration of thealkoxysilyl groups and smaller amount of the tetraalkoxysilane compoundin comparison with the prior art, an anti-contamination coatingcomposition, which is advantageous in view of the performance of thecoat and cost, can be obtained. In the portion of the alkyl group of thecompound (C1), alkyl groups having 1 to 2 carbon atoms and alkyl groupshaving 3 to 10 carbon atoms coexist so that the compatibility with thecomponent (AS) is remarkably improved similar to the other case, therebymaking it possible to form an anti-contamination coating compositionwhich is superior in surface orientation property and physicalproperties of the coat.

To the anti-contamination coating composition of the present invention,it is preferable to further add the hydrophilic alkoxysilane compoundhaving a weight-average molecular weight of 150 to 3500 and containingan alkylene oxide chain having repeating units of 2 to 40 in the solidcontent of 0.1 to 20 parts by weight.

Similar to the above case, when the amount of the compound is less than0.1, sufficient addition effect can not be obtained. When it exceeds 20,the compatibility with the resin component and water resistance of thecured coat are not sufficient.

As described above, the present invention is characterized by using analkoxysilane condensate (C1) or (C2), the substituted alkyl group variesdepending on (C1) or (C2) and its preferable maximal addition amountvaries. This is because the compatibility and physical propertiesimparted to the cured coat vary depending on the objective resincomponent. The optimum combination and the optimum addition amount aredecided according to the resin on the basis of the test.

It is particularly preferred that the alkylene oxide chain of the abovehydrophilic alkoxysilane compound (D) is an ethylene oxide chain becausehigh hydrophilicity can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a shape of an aluminum plate usedfor evaluation of the rain-striped contamination resistance of the coat.

a: Vertical surface during exposure

b: Top surface during exposure

α: Folding angle (135°)

BEST MODE FOR CARRYING OUT THE INVENTION

The following embodiments further illustrate the present invention indetail.

The raw compounds used in the anti-contamination coating composition ofthe present invention are as follows.

(i) Polyurethane-forming Material (PU-I, PU-II, PU-III)

(i-1) Polyol Compound (A1)

The polyol in the present invention means a polyol which is generallyused in the polyurethane technical field, particularly the technicalfield of polyurethane resin coating, and can be a coat-forming elementin the anti-contamination coat formed from an anti-contamination coatingcomposition by mixing with a polyisocyanate compound as a curing agent,followed by the reaction.

Such a polyol includes polyether polyol, polyester polyol, acrylicpolyol or the like. The respective polyols are shown below.

{circle around (1)} Polyether polyol

Examples of the polyether polyol include polyols obtained by adding oneor more kinds of propylene oxide, ethylene oxide, butylene oxide,styrene oxide and the like to one or more kinds of polyhydric alcoholssuch as ethylene glycol, diethylene glycol, propylene glycol,dipropylene glycol, glycerin, trimethylolpropane, pentaerythritol,glucose, sorbitol, sucrose and the like; and polyoxytetramethylenepolyols obtained by adding tetrahydrofuran to the above polyhydricalcohol by ring opening polymerization.

{circle around (2)} Polyester polyol

Examples of the polyester polyol include polyols, for example, condensedpolymers of one or more kinds of low-molecular weight of polyhydricalcohols such as ethylene glycol, propylene glycol, butane diol, pentanediol, hexane diol, cyclohexane dimethanol, glyceline, trimethylolpropane, pentaerythlytol and the like and one or more kinds of glutalicacid, adipic acid, pimelic acid, suberic acid, sebacic acid,telephthalic acid, isophthalic acid, dimer acid, hydrogenated dimeracid, or other low-molecular weight of dicarboxylic acids or oligomeracids etc.; and ring opening polymers of ring opening esters such aspropiolactone, caprolactone, valerolactone and the like.

{circle around (3)} Acrylic polyol

Acrylic polyol is obtained by copolymerizing a monomer having a hydroxylgroup with an acrylic monomer and, if necessary, other monomers. Thosehaving a hydroxyl group can be used without being specifically limited.

Examples of the monomer having a hydroxyl group include the following:

hydroxyalkyl esters of acrylic acid or same hydroxyalkyl esters ofmethacrylic acid: β-hydroxyethyl acrylate, β-hydroxypropyl acrylate,3-hydroxypropyl acrylate, β-hydroxybutyl acrylate, 4-hydroxybutylacrylate, β-hydroxypentyl acrylate, and the like;

acrylate or methacrylate monoesters of polyhydric alcohols such asglycerin, trimethylolpropane and the like; and

N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohols and thelike.

Examples of the acrylic monomer which is copolymerized with the abovehydroxyl group-containing monomer include the followings:

acrylic monomers: methyl acrylate, ethyl acrylate, n-propyl acrylate,isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butylacrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, t-butyl methacrylate, n-hexylmethacrylate, n-octyl methacrylate, n-dodecyl methacrylate, laurylmethacrylate and the like; and

other monomers: styrene, vinyl acetate, acrylonitrile, acrylic acid,methacrylic acid, maleic acid, itaconic acid, acrylamide, glycidylmethacrylate, VeoVa, vinyl chloride, vinylidene chloride and the like.

Among the above monomers, use of methyl acrylate, ethyl acrylate, butylacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethylmethacrylate, butyl methacrylate, lauryl methacrylate, acrylic acid,methacrylic acid, styrene, acrylamide, vinyl acetate and the like areparticularly preferable.

{circle around (4)} Other polyols

In addition, phenol resin polyol, epoxy polyol, polybutadiene polyol,polyisoprene polyol, polyester-polyether polyol, polymer polyol, whichis obtained by vinyl addition or dispersion of polymers of acrylonitrileand styrene, urea-dispersed polyol and carbonate polyol can be used asthe polyol of the present invention.

Among them, acrylic polyol is preferably used when the weatheringresistance of the anti-contamination coat formed from the composition ofthe present invention is taken in consideration.

{circle around (5)} Fluorine-containing copolymer

The fluorine-containing copolymer in the present invention refers tothose obtained by copolymerizing fluoroolefin, at least one of vinylester and vinyl ether, and a hydroxyl group-containing monomer as anessential constitutent component. The fluoroolefin, vinyl ester, andvinyl ether include the following compounds.

{circle around (5)}-a Fluoroolefin

Preferred examples of the fluoroolefin used in the present inventioninclude perfluoroolefins such as tetrafluoroethylene,chlorotrifluoroethylene, hexafluoropropylene and the like; vinylfluoride and vinylidene fluoride.

{circle around (5)}-b Vinyl ester

As a vinyl ester to be copolymerized with the above fluoroolefin in thepresent invention, commercially available ones can be generally used,but Veova-9, a neononanoic acid ethenyl ester, and Veova-10, aneodecanoic acid ethenyl ester, which may alternatively be referred toas vinyl neodecanoate, (manufactured by Shell Chemical Co.) arepreferable in view of the price and characteristics. In addition, vinylacetate, vinyl propionate, vinyl butyrate and vinyl pivalate can beused.

{circle around (5)}-c Vinyl ether

Examples of the vinyl ether used in the present invention include alkylvinyl ethers, monomers having a glycidyl group, such as glycidyl vinylethers and the like. Monomers carboxylated by reacting hydroxyvinylether with anhydrous dibasic acid may also be used. Furthermore, amonomer such as tetrafluoro vinyl ether and vinyl ether having an aminogroup, can also be used. Vinyl ether having two or more vinyl groups canbe optionally used.

{circle around (5)}-d Hydroxyl group-containing monomer

As the monomer to be copolymerized to impart a hydroxyl group to afluorine-containing polymer, the monomers exemplified in the section ofthe above acrylic polyol can be used.

{circle around (5)}-e Optional copolymerizable monomers

In addition to the above essential components, the monomers exemplifiedin the section of above acrylic polyol can be used as an optionalcopolymerizable monomer.

The above fluorine-containing copolymer has a hydroxyl group, but a partof the hydroxyl group may be carboxylated with an anhydrous dibasic acidafter a polymer is formed. Moreover, this fluorine-containing polymermay be used after mixing with other materials such as acrylic resin,polyester resin, acrylic polyol resin, polyester polyol resin and thelike.

As the fluorine-containing copolymer of the present invention (A′),those having a number average molecular weight of 3000 to 30,000, afluorine content of 10 to 30% by weight, a hydroxyl group value of 30 to100 KOH mg/g and a glass transition temperature of 0 to 70° C., which issoluble in solvent, is preferably used.

When the number average molecular weight is smaller than 3000, thereactivity with a curing agent is poor and various physical propertiesof the coat are poor. On the other hand, when it is larger than 30,000,the compatibility with a polyalkyleneoxide chain-containing hydrophilicalkoxysilane compound or a tetraalkoxysilane condensate are poor,unfavorably.

When the fluorine content is smaller than 10% by weight, the weatheringresistance of the resulting coat is insufficient. On the other hand,when it is larger than 30% by weight, the curing property andflexibility of the coat are poor and high gloss value cannot beobtained, unfavorably.

On the other hand, when the hydroxyl group value is smaller than 30 KOHmg/g, the physical properties of the coat and contamination resistanceare poor because of low crosslink density. On the other hand, when it islarger than 100 KOH mg/g, the durability is lowered because shrinkageupon curing by the crosslinking reaction becomes larger.

In addition, when the glass transition temperature is lower than 0° C.,the surface hardness is insufficient to cause physical adhesion ofcontaminants so that eternal contamination, which can not be washed, isformed. On the other hand, when it is higher than 70° C., it is notpreferred because the flexibility of the coat is poor and crack occurswith a lapse of time.

(i-2) Polyol Compounds (A2)

The component (A2) is being dissolved or dispersed in a non-aqueoussolvent, so they can be classified into two classes; those beingdissolved as a dissolving type polyol and those being dispersed as anon-aqueous dispersion type (hereinafter referred to as “NAD type”)polyol.

{circle around (1)} Dissolving type polyols

The dissolving type polyol is that capable of dissolving in anon-aqueous solvent, and specifically polyol having two or more hydroxylgroups in the molecule, and examples thereof include alkyd polyol,acrylic polyol, acrylated alkyd polyol, polyester polyol orpolybutadiene oligomer and the like.

The form of the polyol, which is suitable to be dissolved in thenon-aqueous solvent and has SP of 6.5 to 9.5, include alkyd polyolhaving an oil length of not less than 40%, alkyl polyol containing a rawmaterial having high affinity for a solvent such as p-t-butyl benzoate,and acrylic polyol containing raw materials having high affinity for asolvent having weak dissolving force, such as isobutyl methacrylate,2-ethylhexyl methacrylate or the like.

{circle around (2)} NAD type polyol

The NAD type polyol is dispersed as a resin particle in a non-aqueoussolvent, and has a resin portion, which is soluble in the non-aqueoussolvent, and a resin portion, which is insoluble in the non-aqueoussolvent.

The resin portion, which is soluble in the non-aqueous solvent, is thathaving a solubility of not less than 99.0% by weight. This solubilityvaries depending on the kind of the non-aqueous solvent so that theresin portion may be those, which are soluble in the non-aqueous solventto be dispersed finally.

To the contrary, the resin portion, which is insoluble in thenon-aqueous solvent may be those, which are hardly dissolved in thenon-aqueous solvent or slightly soluble in a very small amount (e.g.having solubility is less than 1.0% by weight). This also variesdepending on the kind of the non-aqueous solvent so that those, whichare hardly dissolved in the non-aqueous solvent to be dispersed finally,are used.

Specific examples thereof include NAD type polyol wherein an acrylicpolyol is used as the resin portion capable of dissolving.

In the present invention, dissolving type polyols or NAD type polyolscan be used alone or in combination thereof as the component (A2).

As the component (A2), those having SP of 6.5 to 9.5 are used. By usingthose having such SP, it is possible to be dissolved and/or dispersed ina solvent having weak solubility, which is referred to as a weaksolvent, and a weak solvent type coating can be provided. As a matter ofcourse, the component can also be used after dissolving in a strongsolvent having strong dissolving force.

(i-3) Polyisocyanate Compound

{circle around (1)} Polyisocyanate compound (B-1)

In the present invention, an anti-contamination coat is formed by mixinga polyisocyanate compound, followed by curing by crosslinking. Thepolyisocyanate compound (B1) used in (PU-I) or (PU-III) includes thefollowing:

polyisocyanate compounds obtained by allophanation, burettization,dimerization (urethidionation), trimerization (isocyanuration),adductation or carbodiimide reaction of isocyanate monomers such astoluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI),polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate(HMDI), isophorone diisocyanate (IPDI), hydrogenated XDI, hydrogenatedMDI and the like, and mixtures thereof.

It is preferred to use aliphatic or alicyclic polyisocyanates ormixtures thereof considering yellowing of the formed coat.

Similar to the polyurethane resin coating which is generally used, thecoating composition of the present invention is preferably a twocomponent type coating comprising a component having a NCO group and acomponent having a hydroxyl group, and these plural components are mixedin a predetermined amount just before use.

Furthermore, these polyisocyanates can be used in the form of a blockedisocyanate using a blocking agent such as alcohols, phenols,ε-caprolactams, oximes, activated methylene compounds. It is preferableto use these polyisocyanates as a solution of a solvent containing noactivated hydrogen.

In the case of using the above blocked isocyanate compounds, therespective components of the anti-contamination coating composition canbe combined to form one package. When this one package type coating isused, NCO can be produced by leaving a blocking agent with heating,etc., after coating and then coating can be cross-linked and cured. Inthis case, the catalyst is preferably used in order to facilitate thereaction of an isocyanate group and a hydroxyl group.

The polyisocyanate compounds (B2) may be used by selecting those havinga concentration of an isocyanate group of 3 to 15% by weight in solidcontent from the above compounds.

In the system containing (PU-I), (PU-III) as the base, mixing of thesepolyisocyanates, polyol compounds and fluorine-containing copolymers iscarried out in the proportion of 0.6 to 1.4, more preferable 0.8 to 1.2in terms of a NCO/OH equivalent ratio (equivalent ratio of isocyanategroup to hydroxyl group). When the NCO/OH equivalent ratio is smallerthan the lower limit of the above range, the curing properties anddurability of the coat are lowered and, at the same time, the so-calledcontamination recovery, i.e., effect of washing out contamination islowered and the stain resistance becomes insufficient. To the contrary,when the NCO/OH equivalent ratio exceeds the above range, excess NCO isreacted with water to evolve CO₂ and bubbles are formed in the coat.Therefore, the finish feeling is lowered or initial dryness isdeteriorated so that the initial anti-contamination performance islowered. Within the range of 0.8 to 1.2, a stable coat can be obtainedeven if a change in the kind of material used and variation in rotsarise. Therefore, the coating shows good elasticity.

{circle around (2)} Polyisocyanate compound (B2)

As the isocyanate compound (B2) used in the (PU-II)-based coatingcomposition, those referred to as an isocyanate curing agent aregenerally suitable and an anti-contamination coat is formed bycrosslinking curing.

Such a curing agent includes alkyl polyisocyanates available under thetrade names Barnoc DN-990, Bamoc DN-991, Barnoc DN-992 (manufactured byDainippon Ink Chemical Industries Co., Ltd.), the alkyl polyisocyanatesavailable under the trade name Duranate TSA (manufactured by AsahikaseiIndustries Co., Ltd.), the alkyl polyisocyanates available under thetrade name Takenate D-177 N (manufactured by Takeda Chemical IndustriesCo., Ltd.), the alkyl polyisocyanates available under the trade nameDesmodule Z-4270 (manufactured by Sumitomo Beyer Urethane Co., Ltd.) orthe like. These curing agents can be suitably used because they are alsosoluble in a solvent having weak solubility.

It is also possible to use those obtained by allophanation, burettion,dimerization (urethidionation), trimerization (isocyanuration),adduction and carbodiimidation reactions of isocyanate monomers such astoluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI),polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate(HMDI), isophorone diisocyanate (IPDI), hydrogenated XDI, hydrogenatedMDI and the like, and mixtures thereof after dissolving in a solventhaving strong dissolving force. It is also suitable to use (PU-II) baseafter dissolving in a weak solvent, similar to the polyol compound.

In the system of (PU-II), the NCO/OH equivalent ratio is preferablywithin the range from 0.7 to 2.0, and more preferably from 0.9 to 1.4.The reason is the same as that in case of (PU-I).

(ii) Tetraalkoxysilane Condensates (C1), (C2)

The tetraalkoxysilane condensate (C1) used in the present invention is atetraalkoxysilane condensate having an average condensation degree of 4to 20, and the condensate is characterized by having an alkyl grouphaving 1 to 2 carbon atoms and an alkyl group having 3 to 10 carbonatoms, the proportion of the alkyl group having 3 to 10 carbon atomsbeing from 5 to 50 equivalent % based on the total alkyl group in thecondensate. Furthermore, the tetraalkoxysilane condensate (C2) is atetraalkoxysilane condensate having an average condensation degree of 4to 20, and the condensate is characterized by having an alkyl grouphaving 1 to 3 carbon atoms and an alkyl group having 4 to 12 carbonatoms, the proportion of the alkyl group having 4 to 12 carbon atomsbeing from 5 to 50 equivalent % based on the total alkyl group in thecondensate.

With regard to the above-mentioned condensates, those having a highdegree of condensation (those having an average condensation degree ofmore than 20) and those having high molecular weight are not preferredbecause it is difficult to produce them and handling of them isinconvenient due to an increase in viscosity. To the contrary, thosehaving an average condensation degree of not more than 3 and lowmolecular weight are not preferred because the volatility becomes higherand the handling is inconvenient.

When the portion of the alkyl group of the above condensate is onlycomposed of an alkyl group of 1 to 2 carbon atoms (alkyl group having 1to 3 carbon atoms in the case of (C2)), the surface orientation propertyis insufficient and the contamination resistance is not satisfactory.When it is composed of only an alkyl group having 3 to 10 carbon atoms,it becomes difficult to cause hydrolysis and the anti-contaminationeffect becomes poor, unsatisfactory. When the alkyl group having 11 ormore carbon atoms (13 or more carbon atoms in the case of (C2))exists,the contamination resistance is lowered, unfavorably. The larger thenumber of carbon atoms of the alkyl group is, the lower a tendency tocause the above hydrolysis reaction becomes so that existence of only analkyl group having large number of carbon atoms is unfavorable.

The alkoxysilane condensates (C1), (C2) of the present invention can beprepared by the method described in the following {circle around (1)},{circle around (2)} using at least one tetraalkoxysilane as the rawmaterial, but the method is not limited thereto. Consequently, it ispreferred that the resulting condensate contains from 5 to 50 equivalent% of the alkyl group having 3 to 10 carbon atoms (alkyl group having 4to 12 carbon atoms in case of (C2)) and has a weight-average molecularweight of 250 to 3500. (C1) and (C2) are selected by testingcharacteristics of resin bases and the compatibility with resin bases.

(ii-{circle around (1)}) Method of condensing a tetraalkoxysilane havingone and more kinds of alkyl groups having 1 or 2 carbon atoms (alkylgroup having 1 to 3 carbon atoms in case of (C2)) and atetraalkoxysilane having one or more kinds of alkyl groups having 3 or10 carbon atoms (alkyl group having 4 to 12 carbon atoms in case of(C2)), or a tetraalkoxysilane having one or more kinds of alkyl groupshaving 1 or 2 carbon atoms (alkyl group having 1 to 3 carbon atoms inthe case of (C2)) and a tetraalkoxysilane having one or more kinds ofalkyl groups having 3 or 10 carbon atoms (alkyl group having 4 to 12carbon atoms in the case of (C2)) as the raw material.

Specific examples of the hydrophilic alkoxysilane compound containing analkyl group having 3 to 10 carbon atoms (alkyl group having 1 to 3carbon atoms in case of (C2)) used as the raw material for preparing thetetraalkoxysilane condensate of the present invention includecondensates such as monobutoxytrimethoxysilane,monopropoxytrimethoxysilane, monopentoxytrimethoxysilane,monohexoxy-trimethoxysilane, dibutoxydiethoxysilane and the like (incase of (C2), monopropoxytrimethoxysilane is omitted anddodecoxytrimethoxysilane can be used), but are not limited thereto.

The tetraalkoxysilanes having 1 or 2 carbon atoms includetetramethoxysilane, tetraethoxysilane and the like(monopropoxytrimethoxysilane can be used in case of (C2)).

(ii-{circle around (2)}) Method of condensing one or moretetraalkoxysilanes so that the average condensation degree becomes 4 to20 by using a publicly known method to obtain a condensate (component(a)) and performing the ester interchange reaction between thecondensate and an alcohol having an alkyl group which is different fromthat of an alkoxysilane as the raw material.

It can also be performed by the method of ester-interchanging about 5 to50% of an alkyl group portion of the component (a) by using an alcohol(component (b)) containing an alkyl group having 3 to 10 carbon atoms(alkyl group having 4 to 12 carbon atoms in case of (C2)).

Specific examples of the component (a) include condensates oftetramethylsilicate, tetraethylsilicate and the like.

It is preferred that the average condensation degree is from 4 to 20 andthe weight-average molecular weight is about from 500 to 3500. When theaverage condensation degree is too large or too small, the handlingbecomes inconvenient, unfavorably.

Specific examples of the component (b) include n-propyl alcohol(excluded in case of (C2)), n-butyl alcohol, n-amyl alcohol, n-hexylalcohol, n-heptyl alcohol, n-octyl alcohol, n-nonyl alcohol, n-decylalcohol and the like (dodecyl alcohol also can be used in case of (C2)),and the component (b) may be alcohols having a branched carbon chain.

When the component (a) is ester-interchanged with the component (b), allalkyl groups (R5) of the component (a) are not ester-interchanged withthe alkyl groups (R6) of the component (b), but about 5 to 50% of allalkyl groups of the component (a) is ester-interchanged.

This interchange ratio is appropriately adjusted with an averagecondensation degree of the component (a), but it is possible to preparethose, wherein the contamination resistance of the coat is excellent, byester interchange of about 5 to 50% of all alkyl groups of the component(a). The lower this ester interchange ratio, the more the contaminationresistance is lowered. When the ester interchange ratio becomes higher,the hydrolysis reaction hardly arises and the coat is hardlyhydrophilized. Therefore, the stain resistance is liable to be lowered.

The above tetraalkoxysilane condensate (C1) is contained in the amountof 1.0 to 40.0 parts by weight, and preferably 2.0 to 30.0 parts byweight in term of SiO₂ relative to 100 parts by weight of the solidcontent of the polyol compound or fluorine-containing copolymer.

The reason is as follows. That is, when the amount is less than 1.0% byweight, the hydrophilicity of the coat is not sufficient and, therefore,the contamination resistance is poor. On the other hand, when the amountexceeds 40.0 parts by weight, there arise problems such as deteriorationof appearance of the cured coat and crack. When it is contained in theamount of 2.0 to 30.0 parts by weight, an influence of the compositionof the material is small and stable characteristics can be obtained.

The value in terms of SiO₂ in the present invention means a weightobtained in the case that all of Si contained in the above alkoxysilanesare converted into SiO₂. Actual calculation was performed by measuring aresidual amount (% by weight) of silica (SiO₂), which is obtained bycompletely hydrolyzing the compound having a Si—O bind, such asalkoxysilane and silicate, followed by calcination at 900° C., andcalculating by the following equation:

[Value in term of SiO₂]=[X]×[Residual amount of silica]

where [X] is an amount of an alkoxysilane condensate added.

(iii) Alkylene Oxide Chain-containing Hydrophilic Alkoxysilane Compound(D)

To the anti-contamination composition of the present invention, ahydrophilic alkoxysilane compound containing an alkylene oxide chain maybe added. This is because the coat becomes more hydrophilious andexcellent effect of contamination resistance is obtained by using incombination with the alkoxysilane condensate (C1). Moreover, by using incombination, it is possible to obtain an anti-contamination coatingcomposition which is superior in stain resistance of the coat.

The hydrophilic alkoxysilane compound (D) is a compound having arepeating unit of an alkylene oxide group and at least one alkoxysilylgroup.

In the repeating unit of the alkylene oxide group, the number of carbonatoms of the alkylene portion is from 2 to 4 and the repeating unit isfrom 2 to 40, and preferably from 2 to 20.

The hydrophilic alkoxysilane compound (D) may have an alkoxysilyl groupat both terminals, or may have an alkoxysilyl group at one terminal andother functional group at the other terminal. The functional group,which can be present at one terminal, includes vinyl group, hydroxylgroup, epoxy group, amino group, isocyanate group, mercapt group or thelike. The functional group may be those which are combined with analkoxysilyl group via an urethane bond, an urea bond, a siloxane bond,an amide bond, or the like.

As the hydrophilic alkoxysilane compound (D), those obtained by reactinga polyalkylene oxide chain-containing compound with an alkoxysilylgroup-containing compound (hereinafter referred to as a “couplingagent”) can be used.

The above polyalkylene oxide chain-containing compound preferably has amolecular weight of 150 to 3500, and more preferably 200 to 1500. Whenthe molecular weight is less than 100, the hydrophilicity of the curedcoat is poor and the washing effect of the contaminant by rainfall cannot be obtained. When the molecular weight exceeds 3500, the waterresistance and hardness of the coat are lowered. When the molecularweight is from 200 to 1500, an influence of the material characteristicsis hardly exerted and the stable characteristics are obtained.

Examples of the polyalkylene oxide chain-containing compound includepolyethylene glycol, polyethylene-propylene glycol,polyethylene-tetramethylene glycol, polyethylene glycol diglycidylether, polypropylene glycol diglycidyl ether, polyoxyethylene diglycolicacid, polyethlene glycol vinyl ether, polyethylene glycol divinyl ether,polyethylene glycol acryl ether, polyethylene glycol diallyl ether orthe like. The polyalkylene oxide chain-containing compound can beselected from the combination of one or more kinds.

On the other hand, the above coupling agent used in the synthesis of thepolyalkylene oxide chain-containing hydrophilic alkoxysilane compound isa compound having at least one alkoxysilyl group and other substituents.Specific examples of the coupling agent includeβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane,N-β-(aminoethyl) γ-aminopropylmethyldimethoxy-silane, N-β-(aminoethyl)γ-aminopropylmethyltrimethoxysilane, γ-aminopropyl-trimethoxysilane,γ-aminopropyltriethoxysilane, isocyanate functional silane,γ-methacryloxypropyltrimethoxysilane,γ-methacryloxypropylmethyldiethoxysilane,γ-methacryloxypropyltriethoxysilane and the like.

Synthesis of the polyalkylene oxide chain-containing hydrophilicalkoxysilane compound (D) is not specifically limited, but it can besynthesized by a publicly known method such as method of preparing apolyalkylene oxide chain-containing compound and a coupling agent,separately, and copolymerizing each compound using a radicalpolymerization initiator when having a polymerizable double bond andmethod of using the addition reaction of an amino group/an epoxy group,an isocyanate group/a hydroxyl group or an isocyanate group/an aminogroup. It is also synthesized by the method of ring opening addition ofethylene oxide to an alkoxysilyl compound having active hydrogen groupsuch as primary or secondary amino group. Hereinafter, the synthesismeans will be described.

Regarding the synthesis method of a polyalkylene oxide chain-containinghydrophilic alkoxysilane compound, in case of copolymerizing using aradical polymerization initiator, the compound can be obtained byreacting at least one polyalkylene oxide chain-containing compoundhaving a polymeric double bond with at least one coupling agent in asuitable non-reactive solvent. In this case, the used radicalpolymerization initiators include perester compounds such as benzoylperoxide, dichlorobenzoyl peroxide,2,5-di(peroxybenzoate)hexine-3,1,3-bis(t-butylperoxyisopropyl)benzene,t-butyl perbenzoate and the like; azo compounds such asazobisisobutylonitrile, dimethylazobutylate and the like; and organicperoxides. As the polyalkylene oxide chain-containing compounds having apolymeric double bond, for example, a polyethyleneglycol vinyl ether canbe used. As the coupling agent, γ-methacryloxypropyltrimethoxysilane,γ-methacryloxypropylmethyldiethoxysilane andγ-methacryloxypropyltriethoxysilane can be used alone or in combinationthereof.

When it is synthesized by the addition reaction of isocyanate/polyol, itis synthesized by mixing a compound having a hydroxyl group at theterminal, such as polyethylene glycol, as a polyalkylene oxidechain-containing compound, and a compound having an isocyanate groupsuch as isocyanate-containing coupling agent as a coupling agent. Inthis synthesis method, it is possible to use a reactive catalyst such asdibutyl tin dilaurate, dibutyl tin dimalate or dioctyl tin dimalate.

As the polyalkylene oxide chain-containing hydrophilic alkoxysilanecompound (D) synthesized by the above reaction, those obtained by addinga coupling agent at both terminals of the polyalkylene oxidechain-containing compound can be obtained, but these compounds can beused alone or in combination thereof.

Among these polyalkylene oxide chain-containing hydrophilic alkoxysilanecompounds, those wherein a polyalkylene oxide chain is an ethylene oxidechain and one terminal is a hydroxyl group are most preferable becausethe anti-contamination effect of the present invention, i.e.contamination resistance and stain resistance are excellent.

The mixing proportion of the hydrophilic alkoxysilane compound (D) isfrom 0.1 to 20 parts by weight, and preferably 0.2 to 10 parts byweight, in terms of the solid content relative to 100 parts by weight ofeach resin solid content of the polyol compound (A1) in case of (PU-I),(PU-III), the polyol compound (A2) in case of (PU-II), and the acryliccopolymer resin (AC) in case of the acrylic copolymer resin (AC). Whenit is less than 0.1 parts by weight, the effect is not obtained,unfavorably. When it exceeds 20 parts by weight, the compatibility withthe resin and the water resistance of the cured article are poor,unfavorably.

(iv) Amine Compound (E)

(iv-{circle around (1)}) The anti-contamination coating composition ofthe present invention is capable of enhancing the interlaminar adhesionof the formed coat by adding the amine compound (E), thereby making itpossible to improve the recoating property. As a result, a firmanti-contamination coat having excellent durability can be obtained.

Examples of the amine compound which can be added for this purposeinclude the following compounds:

primary and secondary amines: ethylamine, dimethylamine, diamylamine,cyclohexylamine, aniline, hexamethylenediamine, ethylenediamine,triethylenediamine and the like;

tertiary amine: trimethylamine, triethylamine, N-methylmorpholine or thelike;

alkanolamine: ethanolamine, diethanolamine, triethanolamine,ethylphenyl-ethanolamine or the like.

other amines: pyridine, morpholine, caprolactum and the like; andaminosilanes: aminomethyltriethoxysilane, aminomethyldiethoxysilane,n-tri-methoxysilylpropyl-ethylenediamine,γ-phenylaminopropyltrimethoxysilane, γ-aminoisopropyltrimethoxysilane,γ-aminoisobutyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane andthe like.

Among the above amine compounds, the tertiary amine compounds can beused, most preferably. Among the tertiary amine compounds, the tertiaryamine compounds having the same or different functional group selectedfrom alkyl group having 1 to 5 carbon atoms, alkanol group having 1 to 5carbon atoms, aminoalkyl group having 1 to 5 carbon atoms andalkoxysilyl group-containing alkyl group having 1 to 5 carbon atoms areparticularly preferable. The reason is that, when amine compounds areprimary amine and secondary amine, a NH group is present and thehydrogen atom is active and is liable to react with a NCO group of theisocyanate. When the NH group and NCO group react each other, an ureabond is formed but the production rate of the urea bond obtained by thereaction of the NH group and NCO group is faster than that of theurethane bond obtained by reacting the OH group and NCO group.Accordingly, the presence of the NH group inhibits production reactionof the urethane bond, and exerts some influence on the properties of thecoat. However, even if the NH group was present, no problem arisesactually considering the addition amount of the amine compound.

The mixing rate of amine compound (E) is 0.02 to 5.0 parts by weight,and preferably 0.05 to 2.0 parts by weight, relative to 100 parts byweight of resin solid content of the polyol compound (A1) in case of(PU-I) and (PU-III), the polyol compound (A2) in case of (PU-II), andthe acryl copolymer resin (AC) in case of the acryl copolymer resin(AC). When the amount of the amine compound is less than 0.02 parts byweight, the effect can not be obtained, unfavorably. On the other hand,when the amount exceeds 5.0 parts by weight, the weathering resistanceof the coat is lowered, resulting in lack of practical use.

This amine compound (E) may be handled similar to normal raw materialsfor coating, and may be added before dispersing in case of a solid, andbefore dispersing or on dissolving after dispersion in case of a liquid.

(iv-{circle around (2)}) Tertiary Amino Group-containingPolyolacrylpolyol

In the anti-contamination coating composition of the present invention,the above polyol (A1) and fluorine-containing copolymer can be used, butthe recoating property can also be improved by using a tertiary aminogroup-containing acrylpolyol or a tertiary amino group andfluorine-containing copolymer in place of adding the amine compound (E).The presence of tertiary amino group gives the same effect as thatobtained by adding an amine compound.

As a tertiary amino group-containing acrylic polyol used with or insteadof the polyol compound (A1), those containing a tertiary amino group canbe used among the acrylic polyols used normally in the technology fieldof polyurethane. Such acrylic polyols include hydroxyl group-containingacrylate ester or methacrylate ester, polymeric unsaturatedbond-containing tertiary amine compound, and copolymer of these and acopolymerizable monomer.

As such hydrogen-containing acrylate or methacrylate, the compoundsdescribed in the item of the acrylic polyol can be used.

On the other hand, examples of the tertiary amine-containing monomercontaining a polymeric unsaturated bond include 2-(N,dimethylamino)ethylmethacrylate, 2-(N,N-dimethylamino)ethylacrylate andthe like.

Among them, particularly preferred is 2-(N,N-dimethylamino)ethylmethacryl ate.

Similarly, as the other monomer capable of copolymerizing with acrylateester or methacrylate ester containing above hydroxyl group, thecompounds described in the item of the acrylic polyol can be used.

Among them, methyl acrylate, ethyl acrylate, butyl acrylate, methylmethacrylate, butyl methacrylate, lauryl methacrylate, acrylic acid,methacrylic acid, styrene, acrylamide, vinyl acetate, etc., areparticularly preferable.

In place of the fluorine-containing copolymer described above, or as thetertiary amino group and fluorine-containing copolymer with thefluorine-containing copolymer, those containing tertiary amino group areused, among normally used fluorine-containing copolymers in thetechnology field of the fluorine resin.

Such a fluorine-containing copolymer is prepared by copolymerizing afluorine monomer and a copolymerizable monomer, which are basicconstituent monomers, with a hydroxyl group-containing acrylate ormethacrylate and a tertiary amine-containing monomer containing apolymerizable unsaturated bond. As the fluorine-containing monomer usedin this copolymerization, general fluorine-containing monomers used inthe above fluorine-containing copolymer can be used.

As the copolymerizable monomer, the above vinyl ether, vinyl ester andacrylate monomer can be used. As the hydroxyl group-containing acrylateor methacrylate and tertiary amine-containing monomer containingpolymeric unsaturated bond, the monomers described in the preparation ofthe above tertiary amino group-containing acrylic polyol can be used.

(v) Acrylic Copolymer Resin (AC)

The acrylic copolymer resin (AC) of the present invention contains anacrylate and/or methacrylate monomer, and an acrylic copolymer resinhaving a glass transition temperature of 0 to 100° C. is used.

As the component (AC), those obtained by appropriately selecting fromthe monomers described as the raw material of the above acrylic polyol,and copolymerizing them, and then dissolving and/or dispersing theresulting copolymer in a non-aqueous solvent, are used. At this time,selection of monomers is carried out so that at least one of selectedmonomers is an acrylate and/or methacrylate monomer.

As the non-aqueous solvent which dissolves and/or disperses thecomponent (AC), general organic solvents can be used, and examplesthereof include aliphatic hydrocarbon solvent, aromatic hydrocarbonsolvent, ester, ketone and the like.

One or more non-aqueous solvents may be used alone or in combination.

As the component (AC), those having a glass transition temperature of 0to 100° C. are used, among the above acrylic copolymer resins.

When the glass transition temperature is not more than 0° C., stickinessof the coat surface referred to as “tack” occurs and physical adhesionof contaminant occurs so that the anti-contamination propertydisappears, unfavorably. To the contrary, when the glass transitiontemperature is larger than 100° C., the hardness of the formed coatbecomes higher so that crazing referred to as “crack” occurs with alapse of time, unfavorably.

When the alkyl groups in the component (C1) to be added in the coatingcontaining the component (AC) as a base include alkyl groups having 1 to2 carbon atoms and alkyl groups 3 to 10 carbon atoms, the surfaceorientation property becomes good and it is possible to obtain excellentanti-contamination effect even in case of smaller addition amount. Aneffect of preventing the anti-contamination coat of the presentinvention from becoming too hard can be obtained by reducing the amountof the component (C1). Furthermore, it became possible to produce acoating at a cheaper price.

The component (C1) thus prepared can be mixed in the amount 1 to 30parts by weight, and preferably 3 to 10 parts by weight, in term of SiO₂relative to 100 parts by weight of the solid content of the resin in thecomponent (AC).

(vi) Acrylic Silicone Resin Base

Alkoxysilyl group-containing acrylic copolymer (AS)(hereinafter referredto as a component (AS)) as one component in the anti-contaminationcoating composition of the present invention is a polymer having atleast one, preferably two or more alkoxysilyl groups represented by thegeneral formula (Chemical Formula 1) in the molecule. This alkoxysilylgroup may be contained in the terminal of the main chain or side chainof the molecule of the component (AS), and may be contained in bothterminals. When the number of alkoxysilyl groups of the molecule of thecomponent (AS) is less than 1, the solvent resistance of the curedarticle, i.e. coat obtained from the composition of the presentinvention tends to be lowered.

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; R₂represents a hydrogen atom or a monovalent hydrocarbon group selectedfrom the group consisting of alkyl, aryl and aralkyl groups having 1 to10 carbon atoms; and a represents 0, 1 or 2.

In Chemical Formula 1, R₁ is an alkyl group having 1 to 10 carbon atoms,preferably 1 to 4 carbon atoms. When the number of carbon atoms of R₁exceeds 10, the reactivity of the alkoxysilyl group is lowered. When R₁is any group other than alkyl group, for example, phenyl group andbenzyl group, the reactivity is also lowered.

Specific examples of the alkyl group represented by R₁ include methylgroup, ethyl group, n-propyl group, isopropyl group, n-butyl group,isobutyl group and the like. In the above formula, R₂ is a hydrogenatom, or a monovalent hydrocarbon selected from the group consisting ofalkyl, aryl and aralkyl groups having 1 to 10 carbon atoms, preferably 1to 4 carbon atoms.

In the hydrocarbon groups represented by R₂, specific examples of thealkyl group include the same group as those for R₁, and specificexamples of the aryl group include phenyl group, and specific examplesof the aralkyl group include benzyl group.

Since the main chain of the component (AS) is substantially composed ofan acrylic copolymer chain, the weathering resistance, chemicalresistance and water resistance of the coat are excellent. In thecomponent (AS), when the alkoxysilyl group is combined with a carbonatom, the water resistance of the resulting cured article becomessuperior and the alkali resistance and acid resistance also becomesuperior.

The number-average molecular weight of the component (AS) is preferablyfrom 1000 to 50000, and more preferably from 3000 to 25000 in view ofphysical properties such as durability of the cured article obtainedfrom the composition of the present invention.

The component (AS) can be obtained by copolymerizing an acrylic monomersuch as acrylic acid, methacrylic acid and derivatives thereof with analkoxysilyl group-containing monomer.

As the acrylic monomer, the monomer described as the acrylic polyol rawmaterial can be used. The following monomers can also be used.

Stearyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl(meth)acrylate, trifluoroethyl (meth)acrylate, pentafluoropropyl(meth)acrylate, perfluorocyclohexyl (meth)acrylate, (meth)acrylonitrile,glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate,diethylaminoethyl (meth)acrylate, methacrylamide, α-ethylmethacrylamide,N-butoxymethylmethacrylamide, N,N-dimethylacrylamide,acryloylmorphorine, N-methylolmethacrylamide and the like.

Phosphate group-containing vinyl compound which is a condensate withphosphoric acid or phosphates, (meth)acrylate containing an urethanebond and a siloxane bond or the like.

Furthermore, the above alkoxysilyl group-containing monomer is notspecifically limited except for having a polymeric double bond, andspecific examples thereof include:

(Chemical Formula 2)

CH₂═CHSi(CH₃)(OCH₃)₂, CH₂═CHSi(OCH₃)₃

CH₂═CHCOO(CH₂)₃SI(CH₃)(OCH₃)₂,

CH₂═CHCOO(CH₂)₃Si(OCH₃)₃,

CH₂═C(CH₃)COO(CH₂)₃Si(CH₃)(OCH₃)₂,

CH₂═C(CH₃)COO(CH₂)₃Si(OCH₃)₃,

CH₂═C(CH₃)COO(CH₂)₃Si(OC₂H₅)₃,

CH₂═C (CH₃)COO(CH₂)₃Si(CH₃)(OC₂H₅)₂

(n represents an integer of 1 to 11), and acrylates or methacrylates,containing an alkoxysilyl group at the terminal via a urethane bond or asiloxane bond.

The proportion of the alkoxysilyl group-containing monomer in thecomponent (AS) is preferably from 5 to 90%, and more preferably from 10to 70% in terms of the curing property of compositions and durability ofthe coat.

In the component (AS), a segment formed on the main chain through aurethane bond and a siloxane bond may be contained in the amount of lessthan 50%, and a segment derived from a monomer except for a methacrylicacid derivative may also be contained.

This monomer is not specifically limited and specific examples thereofinclude aromatic hydrocarbon vinyl compound such as styrene,α-methylstyrene, chlorostyrene, styrene sulfonic acid, 4-hydroxystyrene,vinyl toluene or the like; unsaturated carboxylic acid such as maleicacid, fumaric acid, itaconic acid or the like; salts thereof (alkalimetal salt, ammonium salt, amine salt and the like); acid anhydridesthereof (maleic anhydride and the like); ester of unsaturated carboxylicacid such as diester or half ester of the above carboxylic acids andlinear or branched alcohol having 1 to 20 carbon atoms; vinyl ester andallyl compound, such as vinyl acetate, vinyl propionate, diallylphthalate or the like; amino group-containing vinyl compound such asvinyl pyridine, aminoethyl vinyl ether or the like; amidegroup-containing vinyl compound such as diamide itaconate, crotonamide,diamide malate, diamide fumarate, N-vinyl pyrrolidone or the like; andother vinyl compound such as 2-hydroxyethyl vinyl ether, methyl vinylether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride,chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide,N-vinylimidazol, vinylsulfonic acid and the like.

The alkoxysilyl group-containing acrylic copolymer can be obtained bymixing at least one of these alkoxysilyl group-containing monomers andat least one radical polymerizable monomer in a suitable non-reactivesolvent, and copolymerizing the mixture using a radical polymericinitiator.

Examples of the radical polymeric initiator include perester compoundsuch as benzoyl peroxide, dichlorobenzoyl peroxide,2,5-di(peroxibenzoate)hexine-3,1,3-bis(t-butylperoxiisopropyl)benzene,t-butylperbenzoate or the like; azo compound such asazobisisobutylonitrile, dimethylazobutylate or the like; and organicperoxide.

(vii) Catalyst for Hydrolysis and Condensation of Alkoxysilyl Group (H)

Specific examples of the component (H) used optionally in the presentinvention include the following compounds:

organotin compound: dibutyltin dilaurate, dibutyltin dimalate,dioctyltin dilaurate, dioctyltin dimalate, tin octylate or the like;

phosphoric acid

phosphate: monomethyl phosphate, monoethyl phosphate, monobutylphosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate,diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecylphosphate or the like;

epoxy group-containing compound: propylene oxide, butylene oxide,cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidylether, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl methyldimethoxysilane or the like;

addition reaction product of an epoxy compound and phosphoric acidand/or mono acidic phosphate; and

organic acid and acid anhydride: maleic acid, adipic acid, azelaic acid,sebacic acid, itaconic acid, citric acid, succinic acid, phtharic acid,trimellitic acid, pyromellitic acid and acid anhydrides thereof,p-toluenesulfonic acid or the like.

Furthermore, mixture of these acidic catalysts and amine, or reactionproduct thereof is also included. Examples thereof include amines suchas hexylamine, N,N-dimethyldodecylamine, dodecylamine and the like. Anorganotin compound is preferable and a maleate organotin compound isused, more preferably, because of excellent hydrophilization of the coatsurface in the initial stage of formation of the coat.

The amount of the component (H) is not specifically limited, but it ispreferably from 0.1 to 20 parts by weight, and more preferably from 0.1to 10 parts by weight, relative to 100 parts by weight of the resinsolid content of the component (A). When the amount of the component (D)is less than 0.1 parts by weight, the curing property is lowered. On theother hand, when the amount exceeds 20 parts by weight, the appearanceof the coat tends to be lowered.

(viii) Solvent

In the present invention, the solvent used in the field of the coatingcan be used without being specifically limited. Examples of the organicsolvent include the following.

The solvent having activate hydrogen, which reacts with an isocyanategroup, is not preferable in the coating using an isocyanate compound.

Aliphatic hydrocarbon: n-hexane, n-pentane, n-octane, nonane, decane,undecane, dodecane or the like.

Alicyclic hydrocarbon: cyclohexane, tetrarine, or the like.

Aromatic hydrocarbon: toluene, xylene, solvent naphtha or the like.

Ester compound: ethyl acetate, butyl acetate, isoamyl acetate or thelike.

Ketone compound: methyl ethyl ketone, methyl isobutyl ketone,cyclohexanone or the like.

Others: terpin oil, mineral spirit, ethylcellosolve acetate or the like.

Among the above solvents, an aliphatic hydrocarbon and an alicyclichydrocarbon correspond to a weak solvent, which is a solvent used in(PU-II) and does not have a strong dissolving capability.

(ix) Other Additives

a. The anti-contamination coating composition of the present inventioncan be used as a clear coating composed of only essential componentssuch as resin forming component, alkoxysilyl compound and the like, buta coloring pigment may be mixed to form a colored (enamel) coat. As thecoloring pigment, there can be used an inorganic pigment such astitanium oxide, zinc oxide, carbon black, ferric oxide (red oxide), leadchromate (molybdate orange), chrome yellow, yellow iron oxide, ocher,ultramarine, cobalt green or the like; and an organic pigment such asazo pigment, naphthol pigment, pyrazolone pigment, anthraquinonepigment, perylene pigment, quinacridone pigment, disazo pigment,isoindolinone pigment, benzoimidazol pigment, phthalocyanine pigment,quinophthalone pigment or the like.

b. It is possible to add an extender filler such as ground limestone,clay, kaolin, talc, precipitated barium sulfate, barium carbonate, whitecarbon, diatomaceous earth or the like. Particularly, in case of forminga matte coat, it is optimum to use white carbon and diatomaceous earthhardly affecting the anti-contamination effect on the surface of thecoat. On addition of these inorganic substances to the coating, it ispreferred to treat with a coupling agent on the surface of the powder,and to add a coupling agent to the coating.

In the anti-contamination coating composition of the present invention,various additives, which can be mixed with the coating, can be mixed asfar as the effect of the present invention is not adversely affected.Examples of the additives include plasticizers, preservatives,mildewproofing agents, anti-algae agents, anti-foaming agents, levelingagents, pigment dispersing agents, anti-settling agents, anti-sagagents, delusterants, diluents, ultraviolet absorbers, lightstabilizers, antioxidants and the like.

c. It is possible to optionally use publicly known additives used in thefield of the coating, for example, cellulose such as nitrocellulose,cellulose acetate butylate or the like; resin such as epoxy resin,melamine resin, vinyl chloride resin, polypropylene chloride, chloriderubber, polyvinyl butyral or the like without being specificallylimited.

d. Further, the coating composition of the present invention can bediluted appropriately with a solvent. The solvents are not specificallylimited as far as they do not react with the polyisocyanate compound(B1), and examples thereof include aromatic hydrocarbon, ester, ketoneand aliphatic hydrocarbon solvent.

The storage stability can be improved by using ketones, such as acetone,methyl ethyl ketone, 2-pentanone, 2-hexanone, cyclohexane, alone or incombination as the solvent of the polyisocyanate compound (B1).Moreover, it is preferable to add a water-removing agent such asAdditive TI (manufactured by Beyer Co.) to prevent an isocyanate groupfrom reacting with water, which penetrates into a preserving vessel inorder to inactivate it.

e. A dehydrating agent and/or an alkyl alcohol can be added to thealkoxysilyl group-containing acrylic copolymer resin-basedanti-contamination coating composition, thereby making it possible tosecure the long-term storage stability.

Specific examples of the dehydrating agent include hydrolytic estercompound such as methyl ortho-formate, ethyl ortho-formate, methylortho-acetate, ethyl ortho-acetate, methyltrimethoxysilane,γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or the like.

The alkyl alcohol includes lower molecular weight alcohol such asmethanol, ethanol or the like.

These dehydrating agents and/or alkyl alcohol are preferably added in analkoxysilyl group-containing copolymer (AS).

The amount of the dehydrating agent and/or alkyl alcohol is notspecifically limited, but is preferably from 0.5 to 20 parts by weight,and more preferably 2 to 10 parts by weight, relative to 100 parts byweight of the resin solid content of the component (AS). When thedehydrating agent and alkyl alcohol are used in combination, asignificant effect is obtained in stability, favorably.

Use for Application of Coating, Coating Method

The anti-contamination coating composition of the present invention canbe used in surface finishing of various materials such as metal, glass,ceramic tile, concrete, sizing board, extruded plate, plastics, and thelike, which are used for protecting a substrate such as buildingstructures and civil engineering structures. At this time, theanti-contamination coating composition of the present invention isapplied on the final finishing surface, and it is possible to directlycoat on a base material and to coat on the surface on which any surfacefinishing is applied (undercoating, etc.), but is not specificallylimited.

It is suitable for finishing coating material defined in JIS A 6909(1995), particularly multi-layer finishing coating material, facingmaterial of heavy finishing coating material. Moreover, it can beefficiently used as a facing material of a design coating material suchas facing material of various pattern coating materials, stone-likecoating material, multi-design coating material and the like.

The anti-contamination coating composition of the present invention canbe coated by various methods such as dipping, brushing, spray coating,roller coating, flow coater, roll coater and the like after addingvarious additives to prepare the coating.

EXAMPLES

The feature of the present invention will become more apparent from thefollowing Examples and Comparative Examples.

In the following Examples and Comparative Examples, “parts” are byweight unless otherwise stated.

Synthesis Example (Synthesis Example I) Synthesis Examples ofAlkoxysilane Condensate (Alkyl Silicate condensate)

To 100 parts by weight of an alkyl silicate raw material such as methylsilicate, etc., a predetermined amount of alcohols and 0.03 parts ofdibutyltin dilaurate as a catalyst were added. After mixing, the mixturewas subjected to the demethanolation reaction at 75° C. for 8 hours tosynthesize alkoxysilane condensates 1 to 8, respectively.

With respect to the resulting alkoxysilane condensates, the kind andamount of used alcohols, ester interchange rate, and residual ratio ofsilica after calcination at 900° C. were shown in Table 1, Table 16 andTable 22, respectively.

(Synthesis Example II)

{circle around (1)} Synthesis Example of Polyalkylene OxideChain-containing Alkoxysilane Compound 1

In a reaction vessel equipped with a heater, a stirrer, a refluxcondenser, a dehydrator and a thermometer, 20 parts of PolyethyleneGlycol 200 (average-molecular weight: 200, manufactured by Wako JunyakuCo., Ltd.), 54.3 parts of Y-9030 (manufactured by Nippon Unicar Co.,Ltd.) as an isocyanate-containing silane and 0.05 parts of dibutyltindilaurate were charged, and the mixture was reacted at 50° C. for 8hours to obtain a pale yellow polyethylene oxide chain-containingalkoxysilane compound 1. The weight-average molecular weight of thispolyethylene oxide chain-containing coupling agent was measured in termsof polystyrene by gel permeation chromatography (hereinafter referred toas “GPC”). As a result, it was 800 as converted to polystyrene (In Table3, it was represented by “PEO-alkoxysilane compound 1”).

{circle around (2)} Synthesis Example of Polyalkylene OxideChain-containing Alkoxysilane Compound 2

In a reaction vessel equipped with a heater, a stirrer, a refluxcondenser, a dehydrator and a thermometer, 100 parts of Epolite 40E(average-molecular weight: 170, manufactured by Kyoei-sha Kagaku Co.,Ltd.) and 63.0 parts of A-1100 (manufactured by Nippon Unicar Co., Ltd.)as an amino group-containing silane were charged, and the mixture wasreacted at 50° C. for 8 hours to obtain a pale yellow polyethylene oxidechain-containing coupling agent (2). The weight-average molecular weightof this polyethylene oxide chain-containing coupling agent was measuredin terms of GPC. As a result, it was 980 as converted to polystyrene (InTable 3, it was represented by “PEO-alkoxysilane compound 2”).

(Synthesis Example III) Synthesis Example of Alkyl Silicate Condensates9 to 14

Synthesis Example of Alkyl Silicate Condensate 9

To 100 parts by weight of methyl silicate having a weight-averagemolecular weight of 1000, a condensation degree of about 8 and anonvolatile content of 100% (hereinafter referred to as “methyl silicateA”), 71.4 parts by weight of n-hexyl alcohol and 0.03 parts by weight ofdibutylthin dilaurate as a catalyst were added. After mixing, themixture was subjected to the demethanolation reaction at 75° C. for 8hours to synthesize an alkyl silicate condensate 1.

The ester interchange rate of this alkyl silicate condensate 1 was 39%,and the residual ratio of silica after calcining at 900° C. was 37.6%.

Synthesis Example of Alkyl Silicate Condensate 10

100 parts by weight of methyl silicate A, 17.6 parts by weight of n-amylalcohol and 0.03 parts by weight of dibutyltin dilaurate were mixed inthe same manner as that described in Synthesis Example 1 to synthesizean alkyl silicate condensate 2.

The ester interchange rate of this alkyl silicate condensate 2 was 11%,and the residual ratio of silica was 50.3%.

Synthesis Example of Alkyl Silicate Condensate 11

100 parts by weight of methyl silicate A, 38.4 parts by weight ofn-hexyl alcohol and 0.03 parts by weight of dibutyltin dilaurate weremixed in the same manner as that described in Synthesis Example 1 tosynthesize an alkyl silicate condensate 3.

The ester interchange rate of this alkyl silicate condensate 3 was 22%,and the residual ratio of silica was 43.7%.

Synthesis Example of Alkyl Silicate Condensate 12

100 parts by weight of methyl silicate A, 105.6 parts by weight ofn-amyl alcohol and 0.03 parts by weight of dibutyltin dilaurate weremixed in the same manner as that described in Synthesis Example 1 tosynthesize an alkyl silicate condensate 4.

The ester interchange rate of this alkyl silicate condensate 4 was 67%,and the residual ratio of silica was 33.4%.

Synthesis Example of Alkyl Silicate Condensate 13

100 parts by weight of methyl silicate A, 80.2 parts by weight ofn-tridecyl alcohol and 0.03 parts by weight of dibutyltin dilaurate weremixed in the same manner as that described in Synthesis Example 1 tosynthesize an alkyl silicate condensate 5.

The ester interchange rate of this alkyl silicate condensate 5 was 22%,and the residual ratio of silica was 33.5%.

Synthesis Example of Alkyl Silicate Condensate 14 (Polyalkylene OxideChain-containing Alkoxysilane Compound)

In a reaction vessel equipped with a heater, a stirrer, a refluxcondenser, a dehydrator and a thermometer, 20 parts of PolyethyleneGlycol 200 (average-molecular weight: 200, manufactured by Wako JunyakuCo., Ltd.), 54.3 parts of Y-9030 (manufactured by Nippon Unicar Co.,Ltd.) as an isocyanate-containing silane and 0.05 parts of dibutyltindilaurate were charged, and the mixture was reacted at 50° C. for 8hours to obtain a pale yellow polyethylene oxide chain-containingalkoxysilane compound. The weight-average molecular weight of thispolyethylene oxide chain-containing alkoxysilane compound was measuredin terms of polystyrene by gel permeation chromatography (hereinafterreferred to as “GPC”). As a result, it was 800 as converted topolystyrene.

Examples 1 to 9, Comparative Examples 1 to 7

Test Examples with respect to (PU-I) are as follows.

The formulations of test coatings of the Examples are shown in Table 3,whereas the formulations of test coatings of the Comparative Examplesare shown in Table 4. Characteristics of polyols and fluorine-containingcopolymers, which are used in these formulations, are summarized inTable 2. The isocyanate compound used in the Examples described inTables 3 and 4 is a ketone solution of a trimer of hexamethylenediisocyanate and the NCO content of the liquid is 23.1% by weight.

Examples 10 to 21, Comparative Examples 8 to 16

The test results of a (PU-III)-based anti-contamination coating aredescribed hereinafter.

Elastic coating compositions are prepared using raw materials shown inTable 8 according to the formulation shown in Tables 9 and 10. Namely,80 parts by weight of rutile titanium oxide was mixed relative to 200parts by weight of polyol (100 parts by weight in a solid content) andthe mixture was stirred sufficiently. Subsequently, 3 parts by weight ofcaprolactonediol and 10.7 parts by weight of alkoxysilane compound 1 (5parts by weight in terms of SiO₂) were added to the mixture and then66.7 parts by weight (mixed in NCO/OH equivalent ratio of 1.0) ofisocyanate 1 was added and the mixture was stirred to be an elasticcoating composition. Weathering resistance test, heating/coolingrepeating test, and rain-striped contamination resistance test werecarried out.

Examples 22 to 30, Comparative Example 17 to 25

Using raw materials shown in Table 12, the evaluation was carried outwith respect to the formulations of Tables 13 and 14. Regarding Example28, a pigment was previously dispersed in a polyol 3, and then othercomponents were added to prepare a coating composition, respectively.

Examples 31 to 38, Comparative Example 26 to 33

Among (PU-II)-based coatings, the testing results are shown in Examples31 to 38 and Comparative Examples 26 to 33.

Using raw materials shown in Table 17, the evaluation was carried outwith respect to the formulation of Table 18 in case of the Examples, andthe formulation of Table 19 in case of the Comparative Examples. Theevaluation results are shown in Tables 20 and 21. Good results wereobtained in all Examples. Regarding Example 38, a pigment was previouslydispersed in a polyol 1, and then other components were added to preparea coating composition, respectively.

Examples 39 to 44, Comparative Examples 34 to 41

Examples of the (AC)-based coating are as follows.

Using raw materials shown in Table 23, enamel coatings of Examples 39 to44 and Comparative Examples 34 to 41 were prepared according to theformulations in Table 24. The preparation method is as follows.

Method for Preparation of Coating

100 parts by weight of the solid content of various acrylic resins wasuniformly kneaded with 80 parts by weight of a pigment and varioussilicates or alkoxysilane condensates were added in the proportion shownin Table 3. Furthermore, a polyalkylene oxide chain-containingalkoxysilane compound or polyethylene glycol was mixed (not mixed incase of Comparative Examples 34, 35, 38 and 39) to prepare white enamelcoatings 1 to 14.

Coatings 1 and 2 are those obtained by using normal silicates, whereascoatings 3 to 6 are those obtained by using an alkoxysilane condensateincluding alkyl groups having a chain length of 3 to 10.

Examples 45 to 51. Comparative Examples 42 to 47

Using the Test Examples using the (AS) resin, formulations of testcoatings of the Examples are shown in Table 26 and those of theComparative Examples are shown in Table 27, respectively.

As the alkoxysilyl group-containing acrylic silicon resin, “Zemrac”(manufactured by Kanegafuchi Chemical Industries Co., Ltd.)(averagemolecular weight: 15000, glass transition temperature: 30° C., resinsolid content: 50%) was used. The evaluation results are summarized inTable 28.

Evaluation

The coat was evaluated by the method described below.

(1) Measurement of Contact Angle

The resulting coating composition was spray-coated on an aluminum plateof 150 mm×75 mm×0.8 mm in a dry film thickness of 40 μm to prepare asample.

The resulting sample was dried and aged for 7 days at the standardcondition, and then a contact angle was measured. Subsequently, thesample was dipped in deionized water for 3 hours and the sample wasdried for 18 hours, and then the contact angle was measured. Thisoperation of dipping in deionized water for 3 hours and drying for 18hours was repeated twice, and then the contact angle was measured fourtimes by using a CA-A type contact angle measuring device manufacturedby Kyowa Kaimen Kagaku Co., Ltd. In this test, actual rainfallconditions are artificially made, and used rain is not acidic rain butrain of normal pH.

(2) Anti-contamination Test

A SK#1000 primer (epoxy resin primer, product manufactured by SK KakenCo., Ltd.) was spray-coated on an aluminum plate of 300 mm×150 mm×3.0 mmin dry film thickness of 30 μm, and the plate was dried for 8 hours atstandard state.

Subsequently, the resulting coating composition was spray-coated on analuminum plate, on which the above primer was coated, in a dry filmthickness of 40 μm, and the plate was dried for 7 days at standard stateto obtain a specimen for exposure test.

Outdoor exposure of the sample was carried out at an angle of 45 degreesfacing in the southern direction at Ibaragi-city, Osaka-fu, and then adifference in brightness (ΔL value) was measured at initial stage, after1 month, after 3 months, after 6 months and after 1 year , respectively,and the anti-contamination test was evaluated. The ΔL value was measuredby using a TC-1800 type color-difference meter (manufactured by TokyoDenshoku Co., Ltd.). The smaller the absolute value of ΔL value, thesmaller the change in brightness, resulting in coating having excellentanti-contamination property.

(3) Rain-striped Contamination Resistance Test

An aluminum plate of 300 mm×150 mm×3.0 mm was bent at one third of thelong side to give a plate for exposure. On an obtuse-angle surface ofthis plate for exposure (convex face), the same primer coating as thatapplied on the anti-contamination test sample of (3) and coating of atest coating composition were carried out, and the plate was dried underthe same condition to obtain a sample for exposure.

Outdoor exposure was carried out by placing the resulting sample foroutdoor exposure, a long side formed after bending of said sample beingin a vertical state, facing in the southern direction at Ibaragi-city,Osaka-fu. Evaluations were carried out by visually observing thepresence or absence of rain-striped contamination. The evaluation wasperformed at initial stage, after 1 month, after 3 months, after 6months and after 1 year. The results are evaluated by the following.

{circle around (0)}: No rain-striped contamination is observed.

∘: Trace of rain-striped contamination is observed slightly.

Δ: Trace of rain-striped contamination is observed.

X: Severe trace of rain-striped contamination is observed.

(4) Stain Resistance Test

A coat composed of a primer (30 μm) and a coating (40 μm) was formed onan aluminum plate of 150×70×0.8 mm in the same manner as evaluation (3)and (4) to obtain a sample.

The resulting sample was aged for 7 days at the standard condition and15% by weight of a carbon black water-dispersed paste liquid was droppedon the coat surface so that a drop of a diameter of 20 mm and height of5 mm was formed anti-contamination test according to a stain resistancetest (JIS K-5400 (1990) 8.10). Then, the sample was allowed to stand ina temperature-constant room at 50° C. for 2 hours. Then, the sampleswere washed with flowing water and the degree of contamination of thecoat surface was visually observed. The results are determined accordingto the following criteria.

{circle around (0)}: No contamination is observed.

∘: Trace of contamination is observed slightly.

Δ: Trace of contamination is observed.

X: Severe trace of contamination is observed.

(5) Recoating Test

The above SK#1000 primer was spray-coated on an aluminum plate of 150mm×70 mm×0.8 mm in dry film thickness of 30 sum and the plate was driedfor 8 hours at standard state.

The test coating was spray-coated on four aluminum plates in dry filmthickness of 25 μm, aged and then dried for 16 hours, 1 day, 3 days and7 days, respectively. Subsequently, the same test coating wasspray-coated thereon in a dry film thickness of 25 μm, e.g. total filmthickness of 50 μm to obtain a sample.

The resulting sample was aged for 7 days at the standard state and theadhesion was evaluated according to a cross cut test of the adhesion(JIS K-5400 (1990) 8.8.1). The evaluation results are represented by thescore shown in Table 5.

(6) Lifting Test

Test coatings 1 and 3

A white coating composition of formulation of Example 23 was diluted(outer percentage, diluted by 30% by weight) by adding 100 parts byweight of xylene, and the diluted solution was mixed and stirred toobtain a white test coating I for spray coating.

At that time, the content of the aliphatic hydrocarbon solvent in allsolvents was 37% by weight.

In the same manner, a test coating 3 for coating of Example 31 wasprepared.

Test Coatings 2 and 4

A white coating composition of formulation of Example 23 was furtherdiluted (outer percentage, diluted by 30% by weight) by adding 100 partsby weight of LAWS (Mineral spirit manufactured by Shell Petroleurn OilCo., Ltd.), and the diluted solution was mixed and stirred to obtain awhite test coating 2 for spray coating.

At the time, content ratio of aliphatic hydrocarbon solvent in allsolvents was 68% by weight.

Similarly, a test coating 4 for coating of Example 31 was prepared.

Test Method

On two slate plates of 200 mm×300mm×4 mm, a Milac sealer ES(manufactured by SK Kaken Co., Ltd.; one liquid epoxy resin sealer) wasspray-coated in a desired amount of 0.2 Kg/M², and the plates were driedfor 1 hour at standard state. Then, a SK acrylic color (manufactured bySK Kaken Co., Ltd.; one liquid solvent type acrylic resin topcoat) wasspray-coated in a desired amount of 0.3 Kg/m², and the plates were agedfor 7 days at standard state. Using this coat as an old coat, the abovetest coatings 1, 2, 3 and 4 were spray-coated in a desired amount of0.15 Kg/m², respectively, and the plates were dried for 24 hours atstandard state. Subsequently, each coating was further spray-coated in adesired amount of 0.15 Kg/m.

Results

The state of the coat surface was observed. As a result, the slateplates on which the coatings 1 and 3 were sprayed caused shrink on thesurface and a lifting phenomenon was observed.

The slate plates on which the coatings 2 and 4 were sprayed, have goodsurface condition, and a lifting phenomenon was not observed.

(7) Evaluation of Compatibility

Regarding the PU-II base having specific SP value, a compatibility testwas carried out.

Using raw materials as shown in Tables 12 and 17, each component exceptfor pigments in the formulation shown in Tables 13, 14, 18 and 19 weremixed and the evaluation was performed. That is, 200 parts by weight ofa polyol 3 (solution type acrylic polyol) and 47.0 parts by weight ofisocyanate were mixed (isocyanate was mixed in a NCO/OH ratio of 1.0relative to a hydroxyl group of acrylic polyol), and 10.5 parts byweight of an alkoxysilane condensate was added to the mixture (mixed inthe amount of 5.0 parts by weight in term of SiO₂), and then the mixturewas sufficiently stirred. The resulting mixture was spray-coated on atransparent glass plate of 150 mm×50 mm×3 mm in a dry film thickness of40 μm, and then aged and dried at the temperature of 20° C. and ahumidity of 65% (hereinafter referred to as a “standard state”) for 24hours. Thereafter, the transparency of the film was visually evaluated.

The evaluation was performed according to the following criteria. Theresults are shown in Tables 15 and 20.

∘: Completely transparent state

Δ: The state where slight turbidity is observed

X: Opaque state with white turbidity

(8) Evaluation of Appearance after Curing of Coat

Regarding the acrylic resin (AC)-based coating, the appearance aftercuring of the coat was evaluated.

On seven aluminum plates of 150 mm×75 mm×0.8 mm, a SK#1000 primer (epoxyresin primer, product manufactured by SK Kaken Co., Ltd.) wasspray-coated in a dry film thickness of about 30 μm, and the plates weredried at the temperature of 20° C. and humidity of 65% for 8 hours.

Subsequently, the enamel coating was spray-coated on the surface of theSK#1000 primer of the above aluminum plate in a dry coat thickness of 25μm to obtain a sample.

The sample was aged at the temperature of 20° C. and humidity of 65% for7 days, and the appearance of the coat was evaluated by an appearancetest of the coat according to JIS K5400 7.1. The evaluation wasperformed by the following criteria.

∘: No abnormality is observed. Regarding those wherein abnormality isobserved, the abnormality is concretely described. The results are shownin Table 25.

(9) Weathering Resistance Test

Regarding the coating (PU-III) forming a coat having elasticity, theweathering resistance test was also carried out.

The resulting elastic coating composition was coated on an aluminumplate of 75 mm×75 mm×0.8 mm in a wet thickness of 125 μm by using anapplicator to obtain a test plate. The test plate was aged at thetemperature of 20° C. and a humidity of 65% (hereinafter referred to as“standard state”) for 7 days, and then the weathering resistance testwas carried out using a “Super UV Tester (SUV-W13)” manufactured byIwasaki Denki Co., Ltd.

In the test, a cycle of ultraviolet radiation in an atmosphere of atemperature of 60° C. and a humidity of 65% for 6 hours and standing inan atmosphere of a temperature of 30° C. and a humidity of 90% or morefor 2 hours was repeated 30 times and gloss retention was measured. Thegloss retention (GR) was determined by measuring 60° specular gloss(G0)before testing and 60° specular glossiness(G1) after testing accordingto JIS K 5400 7.6, “specular gloss”, and calculating according to thefollowing equation:

GR(%)=100×G1/G0.

The results are shown in Table 9.

(10) Heating/cooling Repeating Test

Regarding the coating (PU-III) forming a coat having elasticity, theweathering resistance test was also carried out.

Using a slate plate of 150 mm×75 mm×6 mm as a substrate for sample (backand side surfaces (total five surfaces) of each substrate were sealedwith a solvent-free epoxy resin), an EX sealer (manufactured by SK KakenCo., Ltd.: chlorinated rubber type solvent undercoat) was spray-coatedon the substrate to adjust the surface condition in a desired amount of0.2 Kg/m², and the plate was dried for 4 hours at standard state. Then,Lenaexcellent (acrylic rubber waterproofing multi-layer coating materialE manufactured by SK Kaken Co., Ltd.) was spray-coated on the substrateby two portions to adjust the surface condition in a desired amount of0.2 Kg/m². The plates were dried for 24 hours at the standard state.Subsequently, the elastic coating composition was coated by two portionsin a dry film thickness of 50 μm to obtain a sample.

The resulting sample was aged for 7 days at the standard state, and thentested according to JIS A6909 (1995) 6.11, “Heating/cooling repeatingtest”.

After one cycle of 24 hours was carried out ten times, the appearance ofthe coat was evaluated, and then it was evaluated every 10 cycles up to30 cycles (total 3 times of evaluation). The results are shown in Table9.

Evaluation Results Examples 1 to 9, Comparative Examples 1 to 7

The evaluation results are summarized in Table 6. As is apparent fromthese results, the following points can be pointed out.

a) In the anti-contamination coating of the present invention (Examples1 to 9), a decrease in contact angle was observed even in the waterdipping test in which actual rainfall was assumed, and excellentanti-contamination property and rain-striped contamination resistancecould be obtained.

b) In case of the coatings of Examples 1 and 3, good coat can beobtained when topcoating was carried out within 16 hours. In the otherExamples, excellent recoating property was obtained even after a lapseof long time.

c) In case of the conventional polyurethane resin coating (ComparativeExample 1) and fluorine resin coating (Comparative Example 2), which donot contain alkoxysilane or silicates, the contact angle was large andthe contamination resistance and rain-striped contamination resistancewere insufficient.

d) In the coating obtained by adding a normal alkyl silicate(Comparative Example 3), the rain-striped contamination resistance tendsto be improved after a lapse of 6 months or more, but it is insufficientin the initial stage. The recoating property was deteriorated with alapse of time.

e) In case of using an alkoxysilane condensate containing alkyl groupshaving 1 and 12 carbon atoms (Comparative Example 6) or using analkoxysilane condensate containing alkyl groups having 1 and 3 carbonatoms and alkyl groups having 1 and 5 carbon atoms and having anexchange rate of more than 50% (Comparative Examples 4 and 5), thecontamination resistance and rain-striped contamination resistance wereinsufficient.

f) It has been found that coating obtained by adding excess alkoxysilanecondensate (Comparative Example 7) is superior in contaminationresistance and rain-striped contamination resistance in the initialstage, but crack occurs on the whole surface of the coat after threemonths and the durability is insufficient.

Examples 10 to 21, Comparative Examples 8 to 16

It is apparent that the (PU-III)-based coatings of Examples 10 to 21show good weathering resistance, heating/cooling repeating resistanceand high durability. Particularly, Examples 12 and 13 containing apolyalkylene oxide chain-containing alkoxysilane compound show goodresults in the rain-striped contamination test from the initial stage.

On the other hand, Comparative Example 8 using a resin having low Tgshows poor weathering resistance. As a matter of course, thecontamination resistance was also poor. Comparative Example 9 having thesame formulation as that of a normal elastic urethane resin coatingshows sufficient durability, but the contamination resistance was poor.It has been found that the weathering resistance of Comparative Example10 obtained by adding caprolactonediol to a normal elastic urethaneresin coating tends to be deteriorated in comparison with ComparativeExample 9 and, furthermore, blister occurred in the heating/coolingrepeating test and the durability is poor.

It has been found that Comparative Example 11 obtained by mixing methylsilicate with a normal elastic urethane resin coating showedcomparatively good anti-contamination property, but crack occurred inthe heating/cooling repeating test and crack also occurred with a lapseof time in the exposure test of the rain-striped contaminationresistance so that the durability is insufficient. It has been foundthat Comparative Example 12 obtained by adding only the component (C1)of the present invention to a normal elastic urethane resin coating isinferior in durability like Comparative Example 11.

The Example obtained by adding a large amount of the component (G) areinferior in weathering resistance and contamination resistance. It hasbeen found that Comparative Example 14 obtained by mixing a large amountof the component (C1) shows good weathering resistance and contaminationresistance, but crack occurred in the heating/cooling repeating test andcrack also occurred with a lapse of time in the exposure test of therain-striped contamination resistance so that the durability is poor.

Comparative Example 15 obtained by adding an alkoxysilane compound 3containing alkyl groups having 12 carbon atoms shows poor contaminationresistance. Comparative Example 16 obtained by mixing the poylol havinglow Tg and the components (G) and (C1) of the present invention showspoor weathering resistance like Comparative Example 8.

Accordingly, it has been found that there can be obtained a coatingcomposition capable of forming an elastic anti-contamination coat havinggood durability and contamination resistance by mixing the components(A3), (B2), (G), and (C1) of the present invention with good balance.

Examples 22 to 30, Comparative Examples 17 to 25

The results shown in Table 15 were obtained and all Examples showed goodresults. It is apparent that the compatibility between the alkoxysilanecondensate and resin is good and the measured contact angle showsexcellent hydrophilicity. It has also been found that the rain-stripedcontamination was not observed and the contamination resistance isexcellent. In particular, the water dipping test is that whichreproduces actual rainfall several times. It has been found that goodhydrophilicity was shown after rainfall. In particular, Examples 29 and30 obtained by adding the component (D) show good contaminationresistance from the initial stage, and excellent results were obtainedin initial contamination resistance and stain resistance.

Comparative Examples 17 to 19 using a commercially available alkylsilicate had poor compatibility and surface orientation property and,therefore, the surface of the coat is not hydrophilized and rain-stripedcontamination occurred and the contamination resistance is poor. In thecoating of Comparative Example 20, wherein ester interchange rate of analkyl group is high, it is found that rain-striped contaminationoccurred and contamination resistance is bad because surface hardlybecome hydrophilicity. When chain length of alkyl group is too long,rain-striped contamination occurred and contamination resistance becomesworse same as Comparative Example 21 because it does not becomehydrophilicity.

When Comparative Example 22 has normal formulation of weak solvent typecoating, it is found that rain-striped contamination occurred andcontamination resistance is bad because the surface has nohydrophilicity. When the amount of the component (C2) is small, the sameresults were obtained. When the amount of the component (C2) is much,because the component (C2) was oriented to the surface so that itbecomes hydrophilicity, but cure of coat tends to be slower. On theother hand, with time, crack occurred because the surface becomes rigid,thereby bringing results that have problems in durability of a coat.

Examples 31 to 38, Comparative Examples 26 to 33

In the coating of Examples 4 to 7, wherein a polyalkylene oxidechain-containing alkoxysilane compound (D) is contained, lowered ofcontact angle is large owing to repeat of water dipping, surface of coathas hydrophilicity, so that it was found that contamination resistanceat early stage is good. Similarly, the result that stain resistance isexcellent was obtained.

In the coating of Comparative Examples 26 to 28, using commerciallyavailable alkyl silicate, compatibility and surface orientation werebad, so that the surface had no hydrophilicity, rain-stripedcontamination occurred, so that it is found that contaminationresistance was poor. In addition, stain resistance showed bad results.

In the coating of Comparative Example 29, wherein the ester interchangerate of alkyl group of alkoxysilane compound is high, the surface hardlybecomes hydrophilicity, rain-striped contamination occurred, so thatcontamination resistance is bad.

When the chain length of alkyl group is too long, the same asComparative Example 30, it does not become hydrophilicity, so that it isfound that contamination resistance is bad. Comparative Example 31 hasnormal formulation of weak solvent type coating, but it is found thatrain-striped contamination occurred and contamination resistance is bad.In the coating of Comparative Example 32, wherein the amount ofalkoxysilane compound is little and amine compounds are not contained,contamination resistance is bad, the same as Comparative Example 31. Inthe coating of Comparative Example 33, wherein the amount ofalkoxysilane compound is large and no amine compound is contained, coatsurface has hydrophilicity, but there is a problem in interlaminaradhesion and crack occurred because the surface becomes rigid with time,thereby resulting in a problem in durability of a coat. On the otherhand, all Comparative Examples having bad contamination resistance, alsohave bad results in stain resistance.

Example 39 to 44, Comparative Examples 34 to 41

From the results of Table 24, the following evaluation can be obtained.

In particular, it is found that the results of an evaluation forrain-striped contamination in Examples 41 to 44 are excellent. On theother hand, comparing Example 40 with Example 43, in the alkoxysilanecondensate of Example 43, in a small addition amount lowered contactangle can be observed, and excellent results are obtained inrain-striped contamination resistance. Therefore, it was found that inthe case of using the alkoxysilane condensate wherein those having the 3to 10 chains of alkyl group are combined with each other, excellentcontamination resistance can be obtained in a small addition amount. Thecoating of Comparative Example 34 is that same formulation with normalacrylic resin coating, but lowered contact angle was not observed, andbad results were obtained in rain-striped contamination resistance andstain resistance.

On the other hand, the coating of Comparative Example 35, whereinpolyalkylene oxide chain-containing alkoxysilane compound as one ofessential structural element of the present invention is not contained,effect can be observed but, in particular, an inferior result incontamination resistance in the initial stage was obtained.

In addition, in Examples 36 and 37 wherein polyethylene glycol is addedin spite of polyalkylene oxide chain-containing alkoxysilane compound,gloss is lowered, and tack also occurred in the surface of the coat.Therefore, it was found that there are problems in the physicalproperties of the coat and in practical use.

In Comparative Example 38 wherein the alkoxysilane condensate having thechain length of 3 to 10 of alkyl group and high ester interexchangerate, certain effects were observed but they are inefficient results.

In Comparative Example 39 wherein the alkoxysilane condensate having thechain length for alkyl group of 12 is used, the same tendency as coating11 can be observed.

In Comparative Example 40 wherein the addition amount of an alkoxysilanecondensate is little, the same tendency as that in Comparative Example34 was observed, in that it was found that there was little stainresistance.

In contrast, in Comparative Example 41 wherein addition amount ofalkoxylsilane condensate is much, lowered contact angle is observed, butaccording to field exposure crazing called crack occurred in itssurface, so that it was found that there were practical problems.

Examples 45 to 51, Comparative Examples 42 to 47

The evaluation results are collectively shown in Table 28. From thisresult, the following points can be indicated.

1) In the anti-contamination coating composition (Examples 45 to 51),lowered contact angle also can be observed in the water dipping testassuming real rainfall, and excellent contamination resistance andrain-striped contamination resistance are obtained.

2) In particular, according to anti-contamination coating compositioncontaining the component (D) (Examples 48 to 50), the result that from Imonth later, namely from such early state rain-strip is not observed atthe vertical surface.

3) In the anti-contamination coating composition containing no component(C1) of the present invention, result of contamination resistance wasnot observed. On the other hand, at relatively initial stage, thecoating had excellent rain-striped contamination resistance, but withtime rain-strip became obvious.

4) In the anti-contamination coating composition containing thealkoxysilane condensate that is against the specified value according tothe denaturation of the component (C1) (Comparative Examples 42, 45 and46), effect of contamination resistance is not observed, and rain-stripis also obvious.

5) In the anti-contamination coating composition containing thealkoxysilane condensate that is against containing amount of thecomponent (C1) (Comparative Examples 44), coat became brittle, and crackoccurred in all surfaces.

6) In the anti-contamination coating composition containing normalmethyl silicate in spite of denatured silicate of the component (C1)(Comparative Examples 47), appearance of effect in rain-stripedcontamination resistance was not obtained even in the early stage.

TABLE 1 Ester exchange Alcohol used for modification rate NumberAddition Number Resid- of amount of ual Synthetic carbon (parts equiva-ratio of Example Kind atoms by weight) lents (%) SiO₂ Alkoxysilanen-propanol 3 12.0 2 11 53.0 condensate 1 Alkoxysilane n-butanol 4 22.2 317 49.7 condensate 2 Alkoxysilane n-octyl 8 26.0 2 11 46.8 condensate 3alcohol Alkoxysilane n-decyl 10 31.7 2 11 44.7 condensate 4 alcoholAlkoxysilane n-octyl 8 91.1 7 39 33.2 condensate 5 alcohol Alkoxysilanen-propanol 3 60.1 10 56 43.7 condensate 6 Alkoxysilane n-amil 5 141.1 1689 29.5 condensate 7 alcohol Alkoxysilane n-dodecyl 12 37.3 2 11 42.8condensate 8 alcohol Methyl — — — — — 56.0 silicate A Note) Methylsilicate A: weight-average molecular weight: 1000, condensation degree:about 8, nonvolatile content: 100%, The addition amount of alcohol formodification is an addition amount relative to 100 parts by weight ofmethyl silicate A.

TABLE 2 Hydroxyl Resin Weight- group solid average value contentmolecular (KOH Tg (% by Monomer weight mg/g) (° C.) weight) compositionPolyol 1 60,000 50 40 50 Methyl methacrylate, n-Butyl acrylate, Styrene,2-Hydroxyethyl methacrylate Polyol 2 60,000 50 40 50 Methyl methacrylaten-Butyl acrylate, Styrene, N-dimethyl- aminoethyl acrylate2-Hydroxyethyl methacrylate Fluorine-  8,000 100 20 50 Monochlorotri-containing (19 wt %) fluoroethylene, copolymer 1 Ethyl vinyl ether,(content of Beova 9, fluorine) Hydroxybutyl vinyl ether Fluorine-  8,000100 20 50 Monochlorotri- containing (19 wt %) fluoroethylene, copolymer2 Ethyl vinyl ether, (content of Beova 9, fluroine) N-dimethyl-aminoethyl acrylate Hydroxybutyl vinyl ether

TABLE 3 <Composition of coating composition of Examples> Examples 1 2 34 5 6 7 8 9 Polyol 1 100 100 100 (200) (200) (200) Polyol 2 100 100(200) (200) Fluorine-containing copolymer 1 100 100 (200) (200)Fluorine-containing copolymer 2 100 100 (200) (200) Isocyanate [NCO/OHratio] (13.0) (9.8) (45.5) (26.0) (16.2) (19.0) (16.2) (39.0) (32.5)[0.8] [0.6] [1.4] [0.8] [1.0] [1.2] [1.0] [1.2] [1.0] Alkoxysilanecondensate 1 5.0 10.0 (9.4) (18.8) Alkoxysilane condensate 2 8.0 8.0(16.1) (16.1) Alkoxysilane condensate 3 10.0 10.0 (21.4) (21.4)Alkoxysilane condensate 4 20.0 20.2 (44.7) (44.7) Alkoxysilanecondensate 5 35.0 (106) PEO-alkoxysilane compound 1 3.0 5.0PEO-alkoxysilane compound 2 10.0 15.0 Triethylamine 1.0 0.3 0.5 Rutiletitanium oxide 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Note){circle around (1)} The numerical value represents a solid content. Theactual addition amount is given in parentheses. {circle around (2)} Withrespect to the alkoxysilane condensate and silicate, the amount in termof SiO₂ is described. The actual addition amount is given inparentheses.

TABLE 4 <Composition of coating composition of Comparative Examples>Comparative Examples 1 2 3 4 5 6 7 Polyol 1 100 100 100 (200) (200)(200) Polyol 2 100 100 (200) (200) Fluorine-containing copolymer 3 100100 (200) (200) Isocyanate 16.2 32.5 16.2 19.4 32.5 16.2 16.2 [1.0][1.0] [1.0] [1.0] [1.0] [1.0] [1.0] Alkoxysilane condensate 1 45.0(84.9) Alkoxysilane condensate 6 10.0 (22.9) Alkoxysilane condensate 720.0 (67.8) Alkoxysilane condensate 8 15.0 (35.1) Methyl silicate A 10.0(17.9) Rutile titanium oxide 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Note){circle around (1)} The numerical value represents a solid content. Thenumerical value in parentheses is an addition amount of the solution.{circle around (2)} With respect to the alkoxysilane condensate andsilicate, the amount in term of SiO₂ is described and the actualaddition amount is given in parentheses.

TABLE 5 <Evaluation criteria of recoating properties> Rating pointCondition 10 Each one line of a cut is thin and smooth, and there is nopeeling at the cross point of cut and the cross of square. 8 A slightpeeling can be observed at the cross point of cut, but not at the crosssquare. The area of the fracture portion is within 5% of the whole areaof square. 6 Peeling can be observed at both sides of cut and at cross.The area of the fracture portion is within the range from 5 to 15% ofthe whole area of square. 4 The width of peeling based on a cut is wide,and the area of the fracture portion is within the range from 15 to 30%of the whole area of square. 2 The width of peeling based on a cut iswide, and the area of the fracture portion is within the range from 30to 65% of the whole area of square. 0 The area of the fracture portionreaches not less than 65% of the whole area of square.

TABLE 6 <Evaluation results> Examples Comparative Examples 1 2 3 4 5 6 78 9 1 2 3 4 5 6 7 Contact Before dipping in 70 72 69 70 68 58 58 56 5478 90 72 76 92 92 66 angle water (degree) First dipping in 50 52 48 5445 42 40 39 38 78 90 67 72 90 90 42 water Second dipping in 44 46 43 4540 39 39 37 36 78 90 65 70 90 90 34 water Third dipping in 40 41 39 3836 31 30 32 30 78 90 63 68 88 90 29 water Anti- After 1 month −2.4 −2.2−2.0 −2.0 −1.8 −1.0 −0.9 −1.0 −0.8 −6.8 −8.8 −5.6 −6.2 −9.4 −7.0 −1.2staining After 3 months −2.0 −1.8 −1.7 −1.6 −1.5 −1.0 −0.9 −0.9 −0.8−7.8 −9.4 −5.0 −6.0 −10 −7.1 Whole properties After 6 months −1.2 −1.0−1.1 −1.0 −0.9 −0.9 −0.8 −0.7 −0.7 −8.2 −12 −4.2 −5.9 −11 −5.3 area (ΔL)After 1 year −0.8 −0.6 −0.7 −0.9 −0.6 −0.6 −0.7 −0.7 −0.6 −9.4 −14 −3.4−5.2 −13 −4.5 crack occurs Rain- After 1 month ◯ ◯ ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ × × × ×× × ⊚ striped After 3 months ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × × × × × Whole contamiAfter 6 months ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × Δ × × × area nation After 1 year ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × ◯ × × × crack resistance occurs Stain resistance ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × Δ × × × ⊚ Recoating After 16 hours 10 10 10 10 10 1010 10 10 10 10 10 10 10 10 8 properties After 1 day 8 10 8 10 10 10 1010 10 10 10 6 8 8 10 4 After 3 day 0 10 0 10 10 10 10 10 10 10 10 0 0 010 0 After 7 day 0 10 0 10 10 10 10 10 10 10 10 0 0 0 10 0

TABLE 7 Solid Weight-average Hydroxyl Residual ratio of contentmolecular group value Tg SiO₂ Composition/properties (%) weight (KOHmg/g) (° C.) (% by weight) Polyol 3 Monomer composition: methylmethacrylate, 50 40,000 40 50 — n-butyl acrylate, styrene,2-hydroxyethyl methacrylate Polyol 4 Monomer composition: methylmethacrylate, 50 40,000 40 10 — n-butyl acrylate, 2-hydroxyethylmethacrylate Isocyanate 2 NCO content when the solid content is 100% 50— — — — 9%, hexamethylene diisocyanate solution Isocyanate 3 NCO contentwhen the solid content is 100% 50 — — — — 20%, hexamethylenediisocyanate solution Caprolactondiol Liquid 100 2,000 60 — —Caprolactoetriol Liquid 100 600 200  — — Silicate Methyl silicate A, —1,000 — — 56.0 Condensation degree: about 8 Alkoxysilane Described inSynthesis Example I — 1,200 — — 46.8 condensate 3 Alkoxysilane Describedin Synthesis Example I — 1,100 — — 49.7 condensate 2 AlkoxysilaneDescribed in Synthesis Example I — 1,300 — — 42.8 condensate 8 PEO-Described in Synthesis Example II — 800 — — — alkoxysilane compound 1

TABLE 8 Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam-Exam- Exam- ple 10 ple 11 ple 12 ple 13 ple 14 ple 15 ple 16 ple 17 ple18 ple 19 ple 20 ple 21 Polyol 3 200 200 200 200 200 200 200 200 200 200200 200 (100) (100) (100) (100) (100) (100) (100) (100) (100) (100)(100) (100) Polyol 4 Isocyanate 2 66.7 66.7 66.7 53.3 66.7 80.0 66.766.7 66.7 66.7 66.7 66.7 [NCO/OH ratio] (1.0) (1.0) (1.0) (0.8) (1.0)(1.2) (1.0) (1.0) (1.0) (1.0) (1.0) (1.0) Isocyanate 3 [NCO/OH ratio]Caprolactondiol 3 10 10 10 10 15 10 10 15 Caprolactontriol 5 5 15Silicate Alkoxysilane condensate 1 10.7 10.7 10.7 21.4 32.1 (5) (5) (5)(10) (15) Alkoxysilane condensate 2 10.1 20.1 20.1 20.1 10.1 20.1 40.2(5) (10) (10) (10) (5) (10) (20) Alkoxysilane condensate 3 Polyalkyleneoxide chain- 10 5 containing alkoxysilane compound Rutile titanium oxide80 80 80 80 80 80 80 80 80 80 80 80 Regarding the numerical value: thesolid content or the value in term of SiO₂ was described in parentheses.

TABLE 9 Comparative Comparative Comparative Comparative ComparativeComparative Comparative Comparative Comparative Example 8 Example 9Example 10 Example 11 Example 12 Example 13 Example 14 Example 15Example 16 Polyol 3 200 200 200 200 200 200 200 (100) (100) (100) (100)(100) (100) (100) Polyol 4 200 200 (100) (100) Isocyanate 2 66.7 66.753.3 66.7 66.7 80.0 66.7 [NCO/OH ratio] (1.0) (1.0) (0.8) (1.0) (1.0)(1.2) (1.0) Isocyanate 3 30.0 30.0 [NCO/OH ratio] (1.0) (1.0)Caprolactondiol 15 10 10 15 Caprolactontriol 25 Silicate 26.8 (15)Alkoxysilane condensate 1 Alkoxysilane 30.2 20.1 90.5 20.1 condensate 2(15) (10) (45) (10) Alkoxysilane 23.4 condensate 3 (10) Polyalkyleneoxide chain- containing alkoxysilane compound Rutile titanium 80 80 8080 80 80 80 80 80 oxide Regarding the numerical value: the solid contentor the value in term of SiO₂ was described in parentheses.

TABLE 10 Example Example Example Example Example Example 10 11 12 13 1415 Weathering resistance 80 83 77 81 80 75 test (gloss retention %)Heating/ After 10 No No No No No No cooling cycles abnormalityabnormality abnormality abnormality abnormality abnormality repeatingtest After 20 No No No No No No cycles abnormality abnormalityabnormality abnormality abnormality abnormality After 30 No No No No NoNo cycles abnormality abnormality abnormality abnormality abnormalityabnormality Water-striped After 1 ◯ ◯ ⊚ ◯ ◯ ◯ contamination monthresistance test After 2 ◯ ◯ ⊚ ⊚ ⊚ ⊚ months After 3 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ monthsAfter 1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ year Example Example Example Example Example Example16 17 18 19 20 21 Weathering resistance 83 80 78 83 85 80 test (glossretention %) Heating/ After 10 No No No No No No cooling cyclesabnormality abnormality abnormality abnormality abnormality abnormalityrepeating test After 20 No No No No No No cycles abnormality abnormalityabnormality abnormality abnormality abnormality After 30 No No No No NoNo cycles abnormality abnormality abnormality abnormality abnormalityabnormality Water-striped After 1 ◯ ◯ ◯ ◯ ◯ ⊚ contamination monthresistance test After 2 ◯ ◯ ⊚ ◯ ⊚ ⊚ months After 3 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ monthsAfter 1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ year

TABLE 11 Comparative Comparative Comparative Comparative ComparativeComparative Comparative Comparative Comparative Example 8 Example 9Example 10 Example 11 Example 12 Example 13 Example 14 Example 15Example 16 Weathering 58 75 61 79 80 63 81 83 55 resistance test (glossretention %) Heating/ After 10 No No No Crack Crack No Crack No Nocooling cycles abnormality abnormality abnormality occurred occurredabnormality occurred abnormality abnormality repeating After 20 No No No— — No — No No test cycles abnormality abnormality abnormalityabnormality abnormality abnormality After 30 No No Blister — — No — NoNo cycles abnormality abnormality occurred abnormality abnormalityabnormality Water- After 1 × Δ × Δ ⊚ Δ ⊚ Δ Δ striped month contami-After 2 × × × ◯ ⊚ Δ ⊚ × ⊚ nation months resistance After 3 × × × ◯ ⊚ ◯Crack × ⊚ test months occurred After 1 × × × Crack Crack ◯ — × ⊚ yearoccurred occurred

TABLE 12 Polyol 5 Solution grade acrylic polyol, SP:8.7, weight-averagemolecular weight:15000, hydroxyl group value:50 KOH mg/g, nonvolatilecontent:50%, kind of solvent: mineral spirit Polyol 6 NAD grade acrylicpolyol, SP:9.1, weight-average molecular weight:50000, hydroxyl groupvalue:50 KOH mg/g, nonvolatile content:50%, kind of solvent: mineralspirit Isocyanate Mineral spirit solution of isocyanurate type acrylicpolyol of hexamethylene diisocyanate, nonvolatile content:40%, NCOcontent: 8.0% Alkoxysilane Described in Synthesis Example III condensate9 Alkoxysilane Described in Synthesis Example III condensate 10Alkoxysilane Described in Synthesis Example III condensate 11Alkoxysilane Described in Synthesis Example III condensate 12Alkoxysilane Described in Synthesis Example III condensate 13Alkoxysilane Monobutoxytrimethoxysilane low condensate condensate 14(existence proportion of butyl group:22%), condensation degree:about 8,weight-average molecular weight:1000, nonvolatile content: 99.8%,Residual ratio of silica:48.0% by weight PEO-alkoxysilane Described inSynthesis Example II compound 1 Ethyl silicate Weight-average molecularweight:600, nonvolatile content:100%, residual ratio of silica:40% byweight Methyl silicate B Weight-average molecular weight:500,nonvolatile content:100%, residual ratio of silica:51% by weight Methylsilicate A Weight-average molecular weight:1000, nonvolatilecontent:100%, residual ratio of silica:56% by weight Pigment Rutiletitanium oxide

TABLE 13 Example Example Example Example Example Example Example ExampleExample 22 23 24 25 26 27 28 29 30 Polyol 5 200 200 200 200  60 200 200(solid content) (100) (100) (100) (100)  (30) (100) (100) Polyol 6 200200 140 (solid content) (100) (100)  (70) Isocyanate 47.0 47.0 47.0 47.047.0 47.0 47.0 47.0 47.0 [NCO/OH ratio] (1.0) (1.0) (1.0) (1.0) (1.0)(1.0) (1.0) (1.0) (1.0) Alkoxysilane condensate 9 13.3 13.3 Alkoxysilanecondensate 10 29.8 6.0 49.7 11.5 (15.0) (3.0) (25.0) (5.0) Alkoxysilanecondensate 11 34.3 9.2 (15.0) (4.0) Alkoxysilane condensate 12Alkoxysilane condensate 13 Alkoxysilane condensate 14 10.5 (5.0)PEO-alkoxysilane compound 1 3.0 5.0 Ethyl silicate Methyl silicate BMethyl silicate A Pigment 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Unit of all numerical values is “parts by weight”  Regarding silicates,the actual addition amount was described in the upper column, while thevalue in terms of SiO₂ was described in parentheses of the lower column

TABLE 14 Comparative Comparative Comparative Comparative ComparativeComparative Comparative Comparative Comparative Example 17 Example 18Example 19 Example 20 Example 21 Example 22 Example 23 Example 24Example 25 Polyol 5 200 200 200 200 200 200 200 200 200 (solid content)(100) (100) (100) (100) (100) (100) (100) (100) (100) Polyol 6 (solidcontent) Isocyanate 47.0 47.0 61.0 47.0 47.0 47.0 47.0 47.0 47.0 [NCO/OHratio] (1.0) (1.0) (1.3) (1.0) (1.0) (1.0) (1.0) (1.0) (1.0)Alkoxysilane 1.0 160 condensate 9 (0.4) (60.0) Alkoxysilane condensate10 Alkoxysilane condensate 11 Alkoxysilane 30.0 condensate 12 (10.0)Alkoxysilane 29.9 29.9 condensate 13 (5.0) (5.0) Alkoxysilane condensate14 Polyalkylene oxide 3.0 chain-containing alkoxysilane compound Ethylsilicate 12.5 (5.0) Methyl silicate B 20.0 (10.0) Methyl silicate A 17.9(10.0) Pigment 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0  Unit ofall numerical values is “parts by weight”.  Regarding silicates, theactual addition amount was described in the upper column, while thevalue in term of SiO₂ was described in parentheses of the lower column.

TABLE 15 Example 22 Example 23 Example 24 Example 25 Example 26 Example27 Example 28 Example 29 Example 30 Compatibility ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯Contact First 67 65 67 64 67 64 63 56 53 angle Second 61 61 62 58 63 5957 49 47 Third 57 57 58 54 59 54 51 47 44 Fourth 52 53 53 49 55 50 48 4240 Water- After 1 ◯ ◯ ◯ ◯ ◯ ◯ ◯ ⊚ ⊚ striped month contami- After 3 ◯ ◯ ◯⊚ ⊚ ⊚ ⊚ ⊚ ⊚ nation months resistance After 6 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ monthsStain resistance ◯ ◯ ◯ ◯ ◯ ◯ ◯ ⊚ ⊚ Comparative Comparative ComparativeComparative Comparative Comparative Comparative Comparative ComparativeExample 17 Example 18 Example 19 Example 20 Example 21 Example 22Example 23 Example 24 Example 25 Compatibility × × ◯ ◯ ◯ ◯ ◯ ◯ ContactFirst 82 82 82 82 85 85 84 60 75 angle Second 80 81 81 81 84 84 83 59 73(degree) Third 81 80 80 79 80 84 82 58 70 after Fourth 80 81 80 79 80 8382 58 70 water dipping Water- After 1 × × × × × × × Crack × stripedmonth occurred contami- After 3 × × × × × × × on the Δ nation monthssurface resistance After 6 × × × × × × × Δ months Stain resistance × × ×× × × × ◯ Δ

TABLE 16 Ester Kind of silicate Kind of modified alcohol interchangerate Addition Amount Number of Addition amount Number of Amount of SiO₂Kind (parts by weight) carbon atoms Alcohol (parts by weight) mols %Weight % Alkoxysilane condensate 15 Methyl 100 C4 n-butyl 44.4 3 30 40.7silicate B alcohol Alkoxysilane condensate 16 Methyl 100 C6 n-hexyl 20.41 10 4.7 silicate B alcohol Alkoxysilane condensate 17 Methyl 100 C4n-butyl 51.8 7 38 43.2 silicate A alcohol Alkoxysilane condensate 18Methyl 100 C5 n-amyl 35.2 4 22 45.7 silicate A alcohol Alkoxysilanecondensate 19 Methyl 100 C6 n-hexyl 20.4 2 11 49.1 silicate A alcoholAlkoxysilane condensate 20 Methyl 100 C7 n-hepcyl 58.0 5 27 39.4silicate A alcohol Alkoxysilane condensate 21 Methyl 100 C4 n-butyl 88.812 66 37.2 silicate A alcohol Alkoxysilane condensate 22 Methyl 100  C13n-dodecyl 120 6 33 27.8 silicate A alcohol Alkoxysilane condensate 23 C422 48.0 Methyl silicate A 56.0 Methyl silicate B 51.0 Alkoxysilanecondensate: weight-average molecular weight: 1200, average condensationdegree: about 8, nonvolatile content: 99.8% (low condensate ofmonobutoxytrimethoxysilane) Methyl silicate A: weight-average molecularweight: 1000, average condensation degree: about 8, nonvolatile content:100% Methyl silicate B: weight-average molecular weight: 500, averagecondensation degree: about 4, nonvolatile content: 100%

TABLE 17 Polyol 5 Solution grade acrylic polyol, SP:8.7, weight- averagemolecular weight:15000, hydroxyl group value:50 KOH mg/g, nonvolatilecontent:50%, kind of solvent: mineral spirit Polyol 6 NAD grade acrylicpolyol, SP:9.1, weight-average molecular weight:50000, hydroxyl groupvalue:50 KOH mg/g, nonvolatile content:50%, kind of solvent: mineralspirit Isocyanate 4 Mineral spirit solution of isocyanurate type acrylicpolyol of hexamethylene diisocyanate, nonvolatile content:40%, NCOcontent: 8.0% Alkoxysilane Described in Synthesis Example I (see Table16) condensate 15-22 Alkoxysilane Monobutoxytrimethoxysilane lowcondensate condensate 23 (existence proportion of butyl group:22%),condensation degree: about 8, weight-average molecular weight: 1000,nonvolatile content: 99.8%, Residual ratio of silica: 48.0% by weightAmine compound 1 Di n-butylamine Amine compound 2 Triethylamine Ethylsilicate Weight-average molecular weight:600, nonvolatile content:100%,residual ratio of silica:40% by weight Methyl silicate B Weight-averagemolecular weight:500, nonvolatile content:100%, residual ratio ofsilica:51% by weight Methyl silicate A Weight-average molecularweight:1000, nonvolatile content:100%, residual ratio of silica:56% byweight Polyalkylene oxide Described in Synthesis Example IIchain-containing alkoxysilane compound Pigment Rutile titanium oxide

TABLE 18 Example Example Example Example Example Example Example Example31 32 33 34 35 36 37 38 Polyol 5 200 200 200 200 200 200 200 (solidcontent) (100) (100) (100) (100) (100) (100) (100) Polyol 6 200 (solidcontent) (100) Isocyanate 4 47.0 47.0 47.0 61.3 47.0 47.0 47.0 47.0[NCO/OH ratio] (1.0) (1.0) (1.0) (1.3) (1.0) (1.0) (1.0) (1.0)Alkoxysilane condensate 15 12.3 (5.0) Alkoxysilane condensate 16 11.3(5.0) Alkoxysilane condensate 17 11.5 (5.0) Alkoxysilane condensate 1811.0 22.0 (5.0) (11.0) Alkoxysilane condensate 19 20.5 (10.0)Alkoxysilane condensate 20 63.5 (25.0) Alkoxysilane condensate 21Alkoxysilane condensate 22 Alkoxysilane condensate 23 21.0 (10.0) Aminecompound 1 0.3 0.5 0.5 0.3 Amine compound 2 0.3 0.3 0.5 0.1 Ethylsilicate Methyl silicate B Methyl silicate A Polyalkylene oxidechain-containing 10.0 5.0 1.0 3.0 alkoxysilane compound Pigment 80.080.0 80.0 80.0 80.0 80.0 80.0 80.0  Unit of all numerical values is“parts by weight”.  Regarding silicates, the actual addition amount wasdescribed in the upper column, while the value in term of SiO₂ wasdescribed in parentheses of the lower column

TABLE 19 Comparative Comparative Comparative Comparative ComparativeComparative Comparative Comparative Example 26 Example 27 Example 28Example 29 Example 30 Example 31 Example 32 Example 33 Polyol 5 200 200200 200 200 200 200 200 (solid content) (100) (100) (100) (100) (100)(100) (100) (100) Polyol 6 (solid content) Isocyanate 4 47.0 47.0 61.047.0 47.0 47.0 47.0 47.0 [NCO/OH ratio] (1.0) (1.0) (1.3) (1.0) (1.0)(1.0) (1.0) (1.0) Alkoxysilane condensate 15 Alkoxysilane condensate 16Alkoxysilane condensate 17 Alkoxysilane condensate 18 0.9 131 (0.4)(60.0) Alkoxysilane condensate 19 Alkoxysilane condensate 20Alkoxysilane condensate 21 13.5 (5.0) Alkoxysilane condensate 22 36.0(10.0) Alkoxysilane condensate 23 Amine compound 1 0.5 0.5 Aminecompound 2 Ethyl silicate 12.5 (5.0) Methyl silicate B 20.0 (10.0)Methyl silicate A 17.9 (10.0) Polyalkylene oxide chain containingalkoxysilane compound Pigment 80.0 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Unit of all numerical values is “parts by weight”.  Regardingsilicates, the actual addition amount was described in the upper column,while the value in term of SiO₂ was described in parentheses of thelower column

TABLE 20 Example 31 Example 32 Example 33 Example 34 Example 35 Example36 Example 37 Example 38 Compatibility ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Contact angleFirst 67 70 67 62 59 58 60 66 (degree) Second 62 65 60 56 52 50 53 58Third 58 60 57 46 46 44 47 54 Anti- After 1 ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ◯contamination month property After 3 ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ months After 6 ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ ⊚ months Interlaminar After 16 10 10 10 10 10 10 10 10adhesion hours property After 3 10 10 10 10 10 10 10 10 days After 7 1010 10 10 10 10 10 10 days Stain resistance ◯ ◯ ◯ ⊚ ⊚ ⊚ ⊚ ◯

TABLE 21 Comparative Comparative Comparative Comparative ComparativeComparative Comparative Comparative Example Example Example ExampleExample Example Example Example 26 27 28 29 30 31 32 33 Compatibility Δ× ◯ ◯ ◯ — ◯ × Contact First 82 82 82 83 85 85 84 60 angle Second 80 8181 82 83 84 82 59 (degree) Third 79 80 81 81 80 84 80 58 Anti- After 1 ×× × × × × × Crack contamination month occurred on property After 3 × × ×× × × × the surface months After 6 × × × × × × × months InterlaminarAfter 10 10 10 10 10 10 10  8 adhesion 16 property hours After 3 10  810 10 10 10 10  0 days After 7  8  6 10 10 10 10 10  0 days Stainresistance Δ × × × × × × ⊚

TABLE 22 Kind of silicate Kind of modified alcohol Ester interchangeAmount of Addition amount Number of Addition amount Number of SiO₂ Kind(parts by weight) carbons Alcohol (parts by weight) mols % weight %Methyl silicate A — — — — — — — 56.0 Methyl silicate B — — — — — — —59.0 Ethyl silicate — — — — — — — 40.0 Alkoxysilane condensate 24 — — C4— — — 22 48.0 Alkoxysilane condensate 25 Methyl silicate A 100 C4n-butyl alcohol 44.5 6 33 44.7 Alkoxysilane condensate 26 Methylsilicate C 100 C3 n-propil alcohol 13.4 4 13 58.6 Alkoxysilanecondensate 27 Methyl silicate C 100 C7 n-hepcyl alcohol 19.4 3  9 53.7Alkoxysilane condensate 28 Methyl silicate A 100  C10 n-decyl alcohol74.1 10  61 23.4 Alkoxysilane condensate 29 Methyl silicate A 100  C12n-dodecyl alto 37.3 2 11 42.8 Methyl silicate A: weight-averagemolecular weight: 1000, average condensation degree: about 8,nonvolatile content: 100% Methyl silicate C: weight-average molecularweight: 1800, average condensation degree: about 15, nonvolatilecontent: 100% Ethyl silicate: weight-average molecular weight: 700,average condensation degree: about 5, nonvolatile content: 100%Alkoxysilane condensate 24: Monobutoxytrimethoxysilane condensate havinga weight-average molecular weight of 1000, an average condensationdegree of about 8 and a nonvolatile content of 99.8%

TABLE 23 Remarks Acrylic resin 1 weight-average molecular weight:95000,Tg:50° C., resin solid content:50%, monomer composition: methylmethacrylate, vinyl acetate, n-butyl methacrylate Acrylic resin 2weight-average molecular weight:135000, Tg: 10° C., resin solidcontent:50%, monomer composition: methyl methacrylate, 2-ethylhexylacrylate Methyl silicate A weight-average molecular weight:1000,condensation degree:about 8, nonvolatile content:100% Ethyl silicateweight-average molecular weight:700, condensation degree:about 5,nonvolatile content:100% Alkoxysilane Monobutoxytrimethoxysilane lowcondensate condensate 24 (existence proportion of butyl group:22%),condensation degree:about 8, weight-average molecular weight:1000,nonvolatile content:99.8%, Residual ratio of silica:48.0% by weightAlkoxysilane Described in Synthesis Example I (See Table 22) condensate25-29 Polyalkylene oxide Described in Synthesis Example 11chain-containing alkoxysilane compound 1 Polyalkylene oxide Described inSynthesis Example II chain-containing alkoxysilane compound 2Polyethylene PEG-400 manufactured by Kowa Junyaku Co., Ltd., glycol 1number-average molecular weight:400, nonvolatile content:100%Polyethylene PEG-1000 manufactured by Kowa Junyaku Co., glycol 2 Ltd.,number-average molecular weight:1000, nonvolatile content:100% Aminecompound 2 Triethylamine Pigment Rutile titanium oxide  Tg: glasstransition temperature

TABLE 24 Example Example Example Example Example Example ComparativeComparative Comparative 39 40 41 42 43 44 34 35 36 Acrylic resin 1 200200 200 200 200 200 (100) (100) (100) (100) (100) (100) Acrylic resin 2200 200 200 (100) (100) (100) Methyl silicate A Ethyl silicate 25.0 25.0(10.0) (10.0) Alkoxysilane 21.0 21.0 condensate 24 (10.0) (10.0)Alkoxysilane 33.5 condensate 25 (15.0) Alkoxysilane 8.5 8.5 condensate26 (5.0) (5.0) Alkoxysilane 37.0 condensate 27 (20.0) Alkoxysilanecondensate 28 Alkoxysilane condensate 29 Polyalkylene oxide 5.0 3.0 3.0chain-containing alkoxysilane compound 1 Polyalkylene oxide 5.0 5.0chain-containing alkoxysilane compound 2 Polyethylene glycol 1 15.0Polyethylene glycol 2 Amine compound 2 0.3 0.3 Pigment 80.0 80.0 80.080.0 80.0 80.0 80.0 80.0 80.0 Comparative Comparative ComparativeComparative Comparative Example Example Example Example Example 37 38 3940 41 Acrylic resin 1 200 200 200 (100) (100) (100) Acrylic resin 2 200200 (100) (100 Methyl silicate A 18.0 (10.0) Ethyl silicate Alkoxysilanecondensate 24 Alkoxysilane condensate 25 Alkoxysilane 0.9 68.0condensate 26 (0.5) 840.0) Alkoxysilane condensate 27 Alkoxysilane 21.5condensate 28 (5.0) Alkoxysilane 23.5 condensate 29 (10.0) Polyalkyleneoxide 1.0 chain-containing alkoxysilane compound 1 Polyalkylene oxide3.0 chain-containing alkoxysilane compound 2 Polyethylene glycol 1Polyethylene glycol 2 15.0 Amine compound 2 Pigment 80.0 80.0 80.0 80.080.0 Regarding the numerical value, the actual amount is described, andthe solid content was described in parentheses. Regarding silicates, theactual addition amount was described in the upper column, while thevalue in terms of SiO₂ was described in parentheses of the lower column.

TABLE 25 Example Example Example Example Example Example ComparativeComparative Comparative 39 40 41 42 43 44 Example 34 Example 35 Example36 Appearance of the ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ deterioration coat after curing ingloss Water First 56° 64° 60° 58° 59° 56° 83° 78° 70° dipping (contactangle) Second 48° 50° 47° 44° 48° 44° 83° 76° 68° (contact angle) Third40° 43° 42° 40° 41° 38° 83° 76° 64° (contact angle) Water- After 1 ⊚ ◯ ⊚⊚ ⊚ ⊚ × × × striped month contami After 3 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × Δ × nationmonths After 6 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × Δ × months Stain resistance ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × ◯× Remarks Tack occurs on the surface. Comparative ComparativeComparative Comparative Comparative Example 37 Example 38 Example 39Example 40 Example 41 Appearance of the deterioration ◯ ◯ ◯ ◯ coat aftercuring in gloss Water First 66° 74° 76° 72° 54° dipping (contact angle)Second 63° 70° 72° 70° 50° (contact angle) Third 60° 68° 72° 70° 48°(contact angle) Water- After 1 × × × × Crack striped month occurredcontami After 3 × Δ × × on the nation months surface After 6 × Δ × Δmonths Stain resistance × ◯ ◯ ◯ ◯ Remarks Tack occurs on the surface.

TABLE 26 Example Example Example Example Example Example Example 45 4647 48 49 50 51 Alkoxysilyl group-containing 100 100 100 100 100 100 100acrylic resin (200) (200) (200) (200) (200) (200) (200) Alkoxysilanecondensate 1 5.0 8.0 (9.4) (15.1) Alkoxysilane condensate 2 6.0 3.0(12.1) (6.0) Alkoxysilane condensate 3 11.0 (23.5) Alkoxysilanecondensate 4 5.0 (11.2) Alkoxysilane condensate 5 15.0 (45.4)Alkoxysilane condensate 6 Alkoxysilane condensate 7 Alkoxysilanecondensate 8 Methyl silicate A PEO-alkoxysilane compound 1 3.0 5.0PEO-alkoxysilane compound 2 10.0 15.0 10.0 Rutile titanium oxide 80 8080 80 80 80 80 Dibutyltin laurate 2.0 2.0 2.0 Dibutyltin maleate 2.0 2.02.0 2.0 (Note) {circle around (1)} The numerical value represents asolid content. The actual addition amount is described in parentheses.{circle around (2)} Regarding alkoxysilane condensate and silicate, thevalue in terms of SiO₂ was described. The actual addition amount wasdescribed in parentheses.

TABLE 27 Com- Com- Com- Com- Com- Com- para- para- para- para- para-para- tive tive tive tive tive tive Ex- Ex- Ex- Ex- Ex- Ex- ample ampleample ample ample ample 42 43 44 45 46 47 Alkoxysilyl 100 100 100 100100 100 group- (200) (200) (200) (200) (200) (200) containing acrylicresin Alkoxysilane 45.0 condensate 1 (84.9) Alkoxysilane condensate 2Alkoxysilane condensate 3 Alkoxysilane condensate 4 Alkoxysilanecondensate 5 Alkoxysilane 10.0 condensate 6 (22.9) Alkoxysilane 20.0condensate 7 (67.8) Alkoxysilane 15.0 condensate 8 (35.1) Methyl 3.0silicate A (5.4) PEO- 3.0 5.0 3.0 alkoxysilane compound 1 PEO- 15.0 10.0alkoxysilane compound 2 Rutile titanium 80 80 80 80 80 80 oxideDibutyltin 2.0 2.0 2.0 laurate Dibutyltin 2.0 2.0 2.0 maleate (Note){circle around (1)} The numerical value represents a solid content. Theactual addition amount is described in parentheses. {circle around (2)}Regarding alkoxysilane condensate and silicate, the value in term ofSiO₂ was described. The actual addition amount was described inparentheses.

TABLE 28 Example Comparative Examples 45 46 47 48 49 50 51 42 43 44 4546 47 Before dipping in water 69 67 58 56 56 50 56 76 74 66 71 78 60First dipping in water 52 45 40 41 38 48 44 74 70 43 70 76 58 Seconddipping in water 46 41 36 37 34 44 40 72 67 36 68 76 54 Third dipping inwater 40 34 30 29 30 40 36 72 62 30 67 74 54 After 1 month −2.4 −2.2−1.2 −1.0 −1.0 −0.9 −2.0 −6.8 −4.9 −1.4 −5.2 −6.6 −3.6 After 3 months−1.8 −1.6 −1.1 −0.9 −0.9 −0.7 −1.8 −6.6 −5.2 Whole −5.8 −7.1 −2.8 After6 months −1.0 −1.3 −0.9 −0.8 −0.8 −0.6 −1.4 −6.0 −4.7 area −5.1 −9 −1.4After 1 year −0.9 −0.6 −0.7 −0.7 −0.7 −0.6 −0.9 −5.4 −4.0 crack −4.7 −10−1.2 occurred After 1 month ◯ ◯ ⊚ ⊚ ⊚ ⊚ ⊚ × ◯ ⊚ Δ Δ Δ After 3 months ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ × Δ Whole Δ × ◯ After 6 months ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × area × × ⊚After 1 year ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ × × crack × × ⊚ occurred Stain resistance ⊚ ⊚⊚ ⊚ ⊚ ⊚ ⊚ × Δ ⊚ Δ × ⊚

What is claimed is:
 1. An anti-contamination coating compositioncomprising a tetraalkoxysilane condensate (C1) which is atetraalkoxysilane condensate having an average condensation degree of 4to 20 and which has an alkyl group having 1 to 2 carbon atoms and analkyl group having 3 to 10 carbon atoms, the alkyl group having 3 to 10carbon atoms being contained in the amount of 5 to 50% by equivalentbased on all alkyl groups in the condensate, said tetraalkoxysilanecondensate being present in the amount of 1 to 30 parts by weight interm of SiO₂ relative to 100 parts by weight of the solid content of anacrylic copolymer resin (AC) which contains an acrylate and/or amethacrylate monomer and has a glass transition temperature of 0 to 100°C.
 2. The anti-contamination coating composition according to claim 1,further comprising a hydrophilic alkoxysilane compound (D) having aweight-average molecular weight of 150 to 3500 and containing analkylene oxide chain having repeating units of 2 to 40 wherein thehydrophilic alkoxysilane is present in the solid content of 0.1 to 20parts by weight relative to 100 parts by weight of the resin solidcontent of the acrylic copolymer resin (AC).
 3. The anti-contaminationcoating composition according to claim 1, further comprising the aminecompound (E) which is present in the solid content of 0.02 to 5.0 partsby weight relative to 100 parts by weight of the resin solid content ofthe acrylic copolymer resin (AC).
 4. An anti-contamination coatingcomposition comprising a compound (C1) which is a tetraalkoxysilanecondensate having an average condensation degree of 4 to 20 and whichhas an alkyl group having 1 to 2 carbon atoms and an alkyl group having3 to 10 carbon atoms, the alkyl group having 3 to 10 carbon atoms beingcontained in the amount of 5 to 50% by equivalent based on all alkylgroups in the condensate, the tetraalkoxysilane condensate being presentin the amount of 1.0 to 20.0 parts by weight in term of SiO₂ relative to100 parts by weight of the solid content of an alkoxysilylgroup-containing acrylic copolymer resin (AS) which has a grouprepresented by the general formula (chemical formula 1)

wherein R₁ represents an alkyl group having 1 to 10 carbon atoms; R₂represents a hydrogen atom or a monovalent hydrocarbon group selectedfrom the group consisting of alkyl, aryl and aralkyl groups having 1 to10 carbon atoms; and a represents 0, 1 or
 2. 5. The anti-contaminationcoating composition according to claim 4, wherein the content of (C1) isfrom 1.0 to 10 parts by weight relative to 100 parts by weight of thesolid content of the alkoxysilyl group-containing acrylic copolymerresin (AS).
 6. The anti-contamination coating composition according toclaim 4, further comprising the hydrophilic alkoxysilane compound (D)having a weight-average molecular weight of 150 to 3500 and containing apoly alkylene oxide chain having repeating units of 2 to 40 which ispresent in the solid content of 0.1 to 20 parts by weight.